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All questions of Number System for RRB NTPC/ASM/CA/TA Exam
In a three digit number the digit in the unit’s place is twice the digit in the ten’s place and 1.5 times the digit in the hundred’s place. If the sum of all the three digits of the number is 13, what is the number?- a)356
- b)456
- c)436
- d)626
- e)516
Correct answer is option 'C'. Can you explain this answer?
In a three digit number the digit in the unit’s place is twice the digit in the ten’s place and 1.5 times the digit in the hundred’s place. If the sum of all the three digits of the number is 13, what is the number?
a)
356
b)
456
c)
436
d)
626
e)
516
|
Bank Exams India answered |
100a + 10b + c
c = 2b → b = c/2
c = 1.5a → a = c/1.5
c/1.5 + c/2 + c = 13
6.5c = 39
c = 6, b = 3, a = 4 ⇒ 436
c = 2b → b = c/2
c = 1.5a → a = c/1.5
c/1.5 + c/2 + c = 13
6.5c = 39
c = 6, b = 3, a = 4 ⇒ 436
In the examination a candidate must get 2/5 marks to pass, out of total marks.Shiyam appeared in the exam ang got 198 marks and still failed by 36 marks.The maximum mark is
- a)560
- b)610
- c)585
- d)480
- e)None of these
Correct answer is option 'C'. Can you explain this answer?
In the examination a candidate must get 2/5 marks to pass, out of total marks.Shiyam appeared in the exam ang got 198 marks and still failed by 36 marks.The maximum mark is
a)
560
b)
610
c)
585
d)
480
e)
None of these
|
Quantronics answered |
2x = 198+36 = 234
Max = 234*5/2 = 585
Max = 234*5/2 = 585
Sum of three consecutive odd numbers & three consecutive even numbers together is 231. Difference between the smallest odd number and the smallest even number is 11. What is the sum of the largest even number and largest odd number?- a)71
- b)91
- c)101
- d)81
- e)Can not be determined
Correct answer is option 'D'. Can you explain this answer?
Sum of three consecutive odd numbers & three consecutive even numbers together is 231. Difference between the smallest odd number and the smallest even number is 11. What is the sum of the largest even number and largest odd number?
a)
71
b)
91
c)
101
d)
81
e)
Can not be determined
|
|
Kendrika answered |
Let the three odd numbers be x, (x + 2), (x + 4) and
The three even numbers be (x + 11), (x + 13) and (x + 15)
Then,
⇔ x + (x + 2) + (x + 4) + (x + 11) + (x + 13) + (x + 15) = 231
⇔ 6x + 45 = 231
⇔ 6x = 186
⇔ x = 31
∴ Required sum :
= (x + 4) + (x + 15)
= 2x + 19
= 2 × 31 + 19
= 62 + 19
= 81
The three even numbers be (x + 11), (x + 13) and (x + 15)
Then,
⇔ x + (x + 2) + (x + 4) + (x + 11) + (x + 13) + (x + 15) = 231
⇔ 6x + 45 = 231
⇔ 6x = 186
⇔ x = 31
∴ Required sum :
= (x + 4) + (x + 15)
= 2x + 19
= 2 × 31 + 19
= 62 + 19
= 81
In a two digit positive number, the digit at the units place is equal to the square of the digit in ten’s place and the difference between the number and the number obtained by interchanging the digits is 54. What is 40% of the original number?
- a)15.6
- b)37.2
- c)39.4
- d)24.8
- e)None of the Above
Correct answer is option 'A'. Can you explain this answer?
In a two digit positive number, the digit at the units place is equal to the square of the digit in ten’s place and the difference between the number and the number obtained by interchanging the digits is 54. What is 40% of the original number?
a)
15.6
b)
37.2
c)
39.4
d)
24.8
e)
None of the Above
|
Kavya Saxena answered |
A certain number of two digits is three times the sum of its digits. If 45 is added to it, the digits are reversed. The number is _______
- a)16
- b)72
- c)63
- d)27
- e)Can not be determined
Correct answer is option 'D'. Can you explain this answer?
A certain number of two digits is three times the sum of its digits. If 45 is added to it, the digits are reversed. The number is _______
a)
16
b)
72
c)
63
d)
27
e)
Can not be determined
|
KS Coaching Center answered |
A certain number of two digits is three times the sum of its digits only 27 satisfies this condition.
27 + 45 = 72
Therefore Ans is – 27
27 + 45 = 72
Therefore Ans is – 27
There are some Parrots and Some Lions in a forest.If the total number of animals head in forest are 840 and total no of animal legs are 1760.What is the number of Parots in the forest ?- a)800
- b)740
- c)620
- d)590
- e)None of these
Correct answer is option 'A'. Can you explain this answer?
There are some Parrots and Some Lions in a forest.If the total number of animals head in forest are 840 and total no of animal legs are 1760.What is the number of Parots in the forest ?
a)
800
b)
740
c)
620
d)
590
e)
None of these
|
Preeti Khanna answered |
2x+4(840-x) = 1760
2x+3360-4x = 1760
-2x = 1600
X = 1600/2 = 800
2x+3360-4x = 1760
-2x = 1600
X = 1600/2 = 800
The sum of digits of a two digit number is 6. The ratio of the original number to the number formed by interchanging its digits is 4 : 7. Find the number.- a)60
- b)15
- c)42
- d)33
- e)24
Correct answer is option 'E'. Can you explain this answer?
The sum of digits of a two digit number is 6. The ratio of the original number to the number formed by interchanging its digits is 4 : 7. Find the number.
a)
60
b)
15
c)
42
d)
33
e)
24
|
Target Study Academy answered |
Let the number is 10x+y
So x+y = 6
And (10x+y)/(10y+x) = 4/7
Solve, 2x = y and from above we have x+y = 6
Solve both equations, x = 2, y = 4
So x+y = 6
And (10x+y)/(10y+x) = 4/7
Solve, 2x = y and from above we have x+y = 6
Solve both equations, x = 2, y = 4
The sum of two even numbers is six more than twice of the smaller number. If the difference between these two numbers is 6, If the larger number lies between 15 to 25 Which is the smaller number?
- a)16
- b)6
- c)24
- d)12
- e)Can not be determined
Correct answer is option 'D'. Can you explain this answer?
The sum of two even numbers is six more than twice of the smaller number. If the difference between these two numbers is 6, If the larger number lies between 15 to 25 Which is the smaller number?
a)
16
b)
6
c)
24
d)
12
e)
Can not be determined
|
|
Kavya Saxena answered |
If 12 is smaller number then larger number is 18
Sum = (12+18) = 30
Twice of the smaller number = 24.
The sum of two even numbers is six more than twice of the smaller number.
Therefore Number 12 satisfy both the conditions.
Sum = (12+18) = 30
Twice of the smaller number = 24.
The sum of two even numbers is six more than twice of the smaller number.
Therefore Number 12 satisfy both the conditions.
If three numbers are added in pairs, the sums equal to 11,16 and 23.Find the three numbers
- a)8,6,16
- b)9,2,14
- c)9,5,14
- d)7,2,8
Correct answer is option 'B'. Can you explain this answer?
If three numbers are added in pairs, the sums equal to 11,16 and 23.Find the three numbers
a)
8,6,16
b)
9,2,14
c)
9,5,14
d)
7,2,8
|
|
Preeti Khanna answered |
X+y = 11 - (1)
Y+z = 16 - (2)
Z+x = 23 -(3)
Y+z = 16 - (2)
Z+x = 23 -(3)
Add (1), (2), and (3)
2(x + y + z) = 50
X+y+z = 25
X = 25 – 16 = 9
y = 25 – 23 = 2
z = 25 – 11 = 14
X+y+z = 25
X = 25 – 16 = 9
y = 25 – 23 = 2
z = 25 – 11 = 14
Sum of eight consecutive odd numbers is 656. Average of four consecutive even numbers is 87. What is the sum of the largest even number and largest odd number?- a)171
- b)191
- c)101
- d)181
- e)179
Correct answer is option 'E'. Can you explain this answer?
Sum of eight consecutive odd numbers is 656. Average of four consecutive even numbers is 87. What is the sum of the largest even number and largest odd number?
a)
171
b)
191
c)
101
d)
181
e)
179
|
|
Preeti Khanna answered |
odd numbers — x-8, x-6, x-4, x-2, x, x+2, x+4, x+6
x-8 + x-6 + x-4 + x-2 + x + x+2 + x+4 + x+6 = 656
8x – 8 =656
x = 83
Even numbers — y-2, y, y+2, y+4
4y + 4 = 87 * 4
y = 86
sum of the largest even number and odd number = 89 + 90 = 179
x-8 + x-6 + x-4 + x-2 + x + x+2 + x+4 + x+6 = 656
8x – 8 =656
x = 83
Even numbers — y-2, y, y+2, y+4
4y + 4 = 87 * 4
y = 86
sum of the largest even number and odd number = 89 + 90 = 179
When a number is added to 20 percent of the second number, we get 150 percent of the second number. Find the ratio between the first and second number?- a)13:9
- b)12:10
- c)13:10
- d)17:10
- e)None of these
Correct answer is option 'C'. Can you explain this answer?
When a number is added to 20 percent of the second number, we get 150 percent of the second number. Find the ratio between the first and second number?
a)
13:9
b)
12:10
c)
13:10
d)
17:10
e)
None of these
|
|
Bank Exams India answered |
a + (20/100)*b = (150/100)*b
a:b = 13:10
a:b = 13:10
When 1 is added to the numerator of a fraction it becomes 1/4 and 1 is subtracted from the denominator of that fraction it becomes 1/5. Find the fraction.- a)4/19
- b)3/16
- c)5/17
- d)2/15
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
When 1 is added to the numerator of a fraction it becomes 1/4 and 1 is subtracted from the denominator of that fraction it becomes 1/5. Find the fraction.
a)
4/19
b)
3/16
c)
5/17
d)
2/15
e)
None of these
|
|
KS Coaching Center answered |
Let fraction = x/y
Then (x+1)/y = 1/4
And x/(y-1) = 1/5
Solve both equations, x = 3, y = 16
Then (x+1)/y = 1/4
And x/(y-1) = 1/5
Solve both equations, x = 3, y = 16
When a number is subtracted from the number 8,12 and 20, the remainders are in continued proportion, Find the number ?- a)3
- b)4
- c)2
- d)6
Correct answer is option 'B'. Can you explain this answer?
When a number is subtracted from the number 8,12 and 20, the remainders are in continued proportion, Find the number ?
a)
3
b)
4
c)
2
d)
6
|
|
Preeti Khanna answered |
8-x / 12 –x = 12-x /20 –x
(8-x)(20-x) = (12 – x)(12 –x)
160 – 8x – 20x + x2 = 144 – 12x – 12x + x2
4x = 16
x = 4
(8-x)(20-x) = (12 – x)(12 –x)
160 – 8x – 20x + x2 = 144 – 12x – 12x + x2
4x = 16
x = 4
If the sum and the product of 2 numbers are 25 and 144 respectively then the difference of the number should be- a)11
- b)9
- c)7
- d)15
- e)None of these
Correct answer is option 'C'. Can you explain this answer?
If the sum and the product of 2 numbers are 25 and 144 respectively then the difference of the number should be
a)
11
b)
9
c)
7
d)
15
e)
None of these
|
Anaya Patel answered |
A+B = 25
AB = 24
(a-b)2 = (a+b)2 – 4ab
(a-b)2 = 25 – 4(144)
(a-b)2 = 625 – 576
(a-b)2 = 49
a-b = 7
AB = 24
(a-b)2 = (a+b)2 – 4ab
(a-b)2 = 25 – 4(144)
(a-b)2 = 625 – 576
(a-b)2 = 49
a-b = 7
If 4 is added to the numerator of a fraction it becomes 1/3 and if 3 is added to the denominator it becomes 1/6 then find the difference between numerator and denominator is- a)20
- b)21
- c)22
- d)24
- e)None of these
Correct answer is option 'C'. Can you explain this answer?
If 4 is added to the numerator of a fraction it becomes 1/3 and if 3 is added to the denominator it becomes 1/6 then find the difference between numerator and denominator is
a)
20
b)
21
c)
22
d)
24
e)
None of these
|
|
Aisha Gupta answered |
(a +4)/b = 1/3 and a/(b+3) = 1/6 solve both the equations, u will get a = 5 and b = 27
If the positions of the digits of a two digit number are interchanged, the number obtained is smaller than the original number by 27. If the digits of the number are in the ratio of 1:2, what is the original number?
- a)16
- b)32
- c)63
- d)48
- e)Can not be determined
Correct answer is option 'C'. Can you explain this answer?
If the positions of the digits of a two digit number are interchanged, the number obtained is smaller than the original number by 27. If the digits of the number are in the ratio of 1:2, what is the original number?
a)
16
b)
32
c)
63
d)
48
e)
Can not be determined
|
Divey Sethi answered |
original number – 10x + y
(10x + y) – (10y + x) = 27
9(x – y) = 27
x – y = 3
y/x = 1/2
x = 2y
y = 3, x = 6 →63
(10x + y) – (10y + x) = 27
9(x – y) = 27
x – y = 3
y/x = 1/2
x = 2y
y = 3, x = 6 →63
A number is multiplied by 561, and the result obtained is 32,582. But it was found that both 2 in the number are wrong, what should be the correct answer?- a)33,583
- b)37,587
- c)39,589
- d)36,586
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
A number is multiplied by 561, and the result obtained is 32,582. But it was found that both 2 in the number are wrong, what should be the correct answer?
a)
33,583
b)
37,587
c)
39,589
d)
36,586
e)
None of these
|
Saktiprasad Behera answered |
561 is divisible by 11 and 3 but it's multiple
which is given by the qs is 32582 is only divisible by 11 so it's digits sum also can b devide by 3 it's right answer is 37587
which is given by the qs is 32582 is only divisible by 11 so it's digits sum also can b devide by 3 it's right answer is 37587
The sum of the digits of two-digit number is 5. If the digit is reversed, the number is decreased by 27. Find the numbers ?
- a)15,51
- b)41, 14
- c)30, 31
- d)32, 23
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
The sum of the digits of two-digit number is 5. If the digit is reversed, the number is decreased by 27. Find the numbers ?
a)
15,51
b)
41, 14
c)
30, 31
d)
32, 23
e)
None of these
|
Naroj Boda answered |
Let the number be (10a + b)
given, a +b = 5 and (10a + b) – (10b +a) = 27
a – b = 3 and a +b = 5
given, a +b = 5 and (10a + b) – (10b +a) = 27
a – b = 3 and a +b = 5
Sum of the three consecutive number is 1956. What is 23% of the highest number ?- a)150.19
- b)105.19
- c)159.50
- d)150.50
Correct answer is option 'A'. Can you explain this answer?
Sum of the three consecutive number is 1956. What is 23% of the highest number ?
a)
150.19
b)
105.19
c)
159.50
d)
150.50
|
|
Kavya Saxena answered |
X+x+1+x+2 = 1956
3x = 1956 – 3 = 1953
X = 1953/3 = 651
X+3 = 653
23% of largest num = 23*653/100 = 150.19
3x = 1956 – 3 = 1953
X = 1953/3 = 651
X+3 = 653
23% of largest num = 23*653/100 = 150.19
Three numbers are in the ratio 4:3:5. If the difference between thrice the third number and the sum of first and second number is 64. Find the difference between the first and third number?- a)4
- b)8
- c)12
- d)16
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
Three numbers are in the ratio 4:3:5. If the difference between thrice the third number and the sum of first and second number is 64. Find the difference between the first and third number?
a)
4
b)
8
c)
12
d)
16
e)
None of these
|
Cstoppers Instructors answered |
15x – (7x) = 64, we get x = 8
difference between first and third number = 5x – 4x = x = 8
difference between first and third number = 5x – 4x = x = 8
If the numerator of a fraction is increased by 100% and the denominator is increased by 200%. The resultant fraction is 1 (1/15), What was the original fraction ?- a)1(4/3)
- b)1(5/3)
- c)1(3/5)
- d)1(3/2)
Correct answer is option 'C'. Can you explain this answer?
If the numerator of a fraction is increased by 100% and the denominator is increased by 200%. The resultant fraction is 1 (1/15), What was the original fraction ?
a)
1(4/3)
b)
1(5/3)
c)
1(3/5)
d)
1(3/2)
|
|
Aarav Sharma answered |
Given:
- Numerator of a fraction increased by 100%
- Denominator of the same fraction increased by 200%
- Resultant fraction is 1 (1/15)
To find: Original fraction
Approach:
1. Let the original fraction be x/y
2. According to the given condition, (2x/y) / (3y) = 1(1/15)
3. Simplifying the above equation, we get 2x = 5y
4. Dividing both sides by y, we get 2x/y = 5
5. Therefore, the original fraction is 1(3/5)
Answer: Option C (1(3/5))
- Numerator of a fraction increased by 100%
- Denominator of the same fraction increased by 200%
- Resultant fraction is 1 (1/15)
To find: Original fraction
Approach:
1. Let the original fraction be x/y
2. According to the given condition, (2x/y) / (3y) = 1(1/15)
3. Simplifying the above equation, we get 2x = 5y
4. Dividing both sides by y, we get 2x/y = 5
5. Therefore, the original fraction is 1(3/5)
Answer: Option C (1(3/5))
The difference between the digits of a two digit number is 5. Also the original number is 18 more than two times the number obtained by reversing its digits. Find the original number.- a)94
- b)61
- c)72
- d)49
- e)27
Correct answer is option 'C'. Can you explain this answer?
The difference between the digits of a two digit number is 5. Also the original number is 18 more than two times the number obtained by reversing its digits. Find the original number.
a)
94
b)
61
c)
72
d)
49
e)
27
|
Ravi Singh answered |
Let number is 10x+y
Then x-y = 5 or y-x = 5
Now given that, 10x+y = 2(10y+x) + 18 Solve, 8x – 19y = 18
Now solve: 8x – 19y = 18 and x-y = 5. In this y = 2, x = 7
And also solve; 8x – 19y = 18 and y-x = 5. In this y come to be negative which is not possible so discard this
So number is 10*7 + 2
Then x-y = 5 or y-x = 5
Now given that, 10x+y = 2(10y+x) + 18 Solve, 8x – 19y = 18
Now solve: 8x – 19y = 18 and x-y = 5. In this y = 2, x = 7
And also solve; 8x – 19y = 18 and y-x = 5. In this y come to be negative which is not possible so discard this
So number is 10*7 + 2
A number gets reduced to its two-third when 24 is subtracted from it. Find oneeighth of the number?- a)7
- b)8
- c)9
- d)10
- e)None of these
Correct answer is option 'C'. Can you explain this answer?
A number gets reduced to its two-third when 24 is subtracted from it. Find oneeighth of the number?
a)
7
b)
8
c)
9
d)
10
e)
None of these
|
|
Aarav Sharma answered |
Given: A number gets reduced to its two-third when 24 is subtracted from it.
Let the number be x.
According to the given condition, we can write:
x - 24 = (2/3)x
Multiplying both sides by 3, we get:
3x - 72 = 2x
Simplifying, we get:
x = 72
We need to find one-eighth of the number, which is:
(1/8) x 72 = 9
Therefore, the answer is option (c) 9.
Let the number be x.
According to the given condition, we can write:
x - 24 = (2/3)x
Multiplying both sides by 3, we get:
3x - 72 = 2x
Simplifying, we get:
x = 72
We need to find one-eighth of the number, which is:
(1/8) x 72 = 9
Therefore, the answer is option (c) 9.
When one-fourth of a number is added to 16, it becomes three-fourth of itself. Find the number?
- a)24
- b)32
- c)36
- d)48
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
When one-fourth of a number is added to 16, it becomes three-fourth of itself. Find the number?
a)
24
b)
32
c)
36
d)
48
e)
None of these
|
Yash Patel answered |
Solution:
Let the number be x.
According to the given condition:
- (1/4)x + 16 = (3/4)x
Solve for x:
- (1/4)x + 16 = (3/4)x
- 16 = (3/4)x - (1/4)x
- 16 = (2/4)x
- 16 = (1/2)x
- x = 32
Therefore, the number is 32.
Answer: B: 32
Let the number be x.
According to the given condition:
- (1/4)x + 16 = (3/4)x
Solve for x:
- (1/4)x + 16 = (3/4)x
- 16 = (3/4)x - (1/4)x
- 16 = (2/4)x
- 16 = (1/2)x
- x = 32
Therefore, the number is 32.
Answer: B: 32
If the divisor is five times the quotient and six times the remainder, if the remainder is 5 then the dividend is- a)225
- b)300
- c)185
- d)412
- e)None of these
Correct answer is option 'C'. Can you explain this answer?
If the divisor is five times the quotient and six times the remainder, if the remainder is 5 then the dividend is
a)
225
b)
300
c)
185
d)
412
e)
None of these
|
|
Aisha Gupta answered |
Q=6, R = 5
Dividend = divisor*Q + R
Dividend = 30*6 + 5 = 180+5 = 185
Dividend = divisor*Q + R
Dividend = 30*6 + 5 = 180+5 = 185
A number is divided by 2, 3, 4, 5 or 6, reminder in each case is one. But the number is exactly divisible by 7. The number lies between 250 and 350, the sum of digits of the number will be
- a)4
- b)7
- c)6
- d)10
- e)Can not be determined
Correct answer is option 'A'. Can you explain this answer?
A number is divided by 2, 3, 4, 5 or 6, reminder in each case is one. But the number is exactly divisible by 7. The number lies between 250 and 350, the sum of digits of the number will be
a)
4
b)
7
c)
6
d)
10
e)
Can not be determined
|
|
Preeti Khanna answered |
To solve this problem, we need to find a number that satisfies the following conditions:
- When divided by 2, 3, 4, 5, or 6, the remainder is 1.
- The number is divisible by 7.
- The number lies between 250 and 350.
Let's start by finding the least common multiple (LCM) of 2, 3, 4, 5, and 6, which is the smallest number divisible by all of these numbers.
LCM(2, 3, 4, 5, 6) = 60
We need to find a number of the form 7k, where k is an integer, that leaves a remainder of 1 when divided by 60. The numbers in this sequence can be expressed as 60n + 1, where n is an integer.
Now, let's find the first few numbers of the form 60n + 1 that are divisible by 7 and lie between 250 and 350:
- For n = 4: 60(4) + 1 = 241 (not divisible by 7)
- For n = 5: 60(5) + 1 = 301 (divisible by 7)
So, the number we're looking for is 301.
Now, let's find the sum of its digits: 3 + 0 + 1 = 4
Therefore, the sum of the digits of the number is 4.
The sum of square of 2 number is 1972 and the difference of their square is 620. Find the number ?- a)33,26
- b)34,25
- c)36,26
- d)38,28
Correct answer is option 'C'. Can you explain this answer?
The sum of square of 2 number is 1972 and the difference of their square is 620. Find the number ?
a)
33,26
b)
34,25
c)
36,26
d)
38,28
|
|
Aisha Gupta answered |
X2 + y2 = 1972
X2 – y2 = 620
Solve this
2x2 = 2592
x = 1296
x = 36
y2 = 1972 – 1296
y2 = 676
y = 26
X2 – y2 = 620
Solve this
2x2 = 2592
x = 1296
x = 36
y2 = 1972 – 1296
y2 = 676
y = 26
If 4 is added to the numerator of a fraction it becomes 1/3 and if 3 is added to the denominator it becomes 1/6 then find the numerator and denominator is
- a)5/26
- b)25/4
- c)6/17
- d)5/27
- e)None of these
Correct answer is option 'D'. Can you explain this answer?
If 4 is added to the numerator of a fraction it becomes 1/3 and if 3 is added to the denominator it becomes 1/6 then find the numerator and denominator is
a)
5/26
b)
25/4
c)
6/17
d)
5/27
e)
None of these
|
|
Preeti Khanna answered |
Let the numerator be x and denominator be y
Fraction will be x/y
According to the question
(x + 4)/y = 1/3
⇒ 3x + 12 = y ......(1)
Now,
x/(y + 3) = 1/6
⇒ 6x = y + 3 ......(2)
Solving both the equations we get
x = 5 and y = 27
So , fraction x/y = 5/27
The number obtained by interchanging the two digits of a two digit number is less than the original number by 27. If the difference between the two digits of the number is 3, then what is the original number?- a)64
- b)72
- c)65
- d)73
- e)None of the Above
Correct answer is option 'E'. Can you explain this answer?
The number obtained by interchanging the two digits of a two digit number is less than the original number by 27. If the difference between the two digits of the number is 3, then what is the original number?
a)
64
b)
72
c)
65
d)
73
e)
None of the Above
|
|
Kavya Saxena answered |
original number – 10x + y
(10x + y) – (10y + x) = 27
9(x – y) = 27
x – y = 3
All the given options not follow the condition.
(10x + y) – (10y + x) = 27
9(x – y) = 27
x – y = 3
All the given options not follow the condition.
25% of a number is 2 time 65% of another number.Find the ratio of the second no to the first number ?- a)5:26
- b)26:5
- c)23:7
- d)5:23
Correct answer is option 'A'. Can you explain this answer?
25% of a number is 2 time 65% of another number.Find the ratio of the second no to the first number ?
a)
5:26
b)
26:5
c)
23:7
d)
5:23
|
|
Ravi Singh answered |
(a*25)/100 = b(2*65)/100
a*25 = b*130
a/b = 130/25 = 26/5
b:a = 5:26
a*25 = b*130
a/b = 130/25 = 26/5
b:a = 5:26
The sum of the digits of a two-digit number is 6. If the digits are reversed, the number is decreased by 36. Find the number?- a)15
- b)51
- c)24
- d)42
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
The sum of the digits of a two-digit number is 6. If the digits are reversed, the number is decreased by 36. Find the number?
a)
15
b)
51
c)
24
d)
42
e)
None of these
|
|
Anaya Patel answered |
a + b = 6
(10a + b) – (10b +a) = 36, a – b = 4
We get a = 5 and b = 1
So number is 51
(10a + b) – (10b +a) = 36, a – b = 4
We get a = 5 and b = 1
So number is 51
When a number is multiplied by 13 and 13 is added to the product, the resultant is divisible by 5. Find the smallest product possible?- a)85
- b)130
- c)65
- d)90
- e)105
Correct answer is option 'C'. Can you explain this answer?
When a number is multiplied by 13 and 13 is added to the product, the resultant is divisible by 5. Find the smallest product possible?
a)
85
b)
130
c)
65
d)
90
e)
105
|
|
Alok Verma answered |
13x + 13 which is divisible by 5, or 13(x+1) should be divisible by 5. The smallest value of x = 4 to be put here to make it divisible by 5. So the number is 13(4+1)
Micael gets 3 marks for each correct questions and loses 2 marks for each wrong answers.He attempts 30 sum and obtain 30 marks.Find the no of Questions he answered correctly ?
- a)18
- b)12
- c)23
- d)20
- e)None of these
Correct answer is option 'A'. Can you explain this answer?
Micael gets 3 marks for each correct questions and loses 2 marks for each wrong answers.He attempts 30 sum and obtain 30 marks.Find the no of Questions he answered correctly ?
a)
18
b)
12
c)
23
d)
20
e)
None of these
|
|
Anaya Patel answered |
let x be the no of correct answer
x+y=30
3x-2y=30
2x+2y=60
5x=90
x=18
x+y=30
3x-2y=30
2x+2y=60
5x=90
x=18
12 +22 +……………………………………+242- a)3800
- b)4900
- c)5100
- d)5430
- e)None of these
Correct answer is option 'B'. Can you explain this answer?
12 +22 +……………………………………+242
a)
3800
b)
4900
c)
5100
d)
5430
e)
None of these
|
Faizan Khan answered |
Sum of square number = n(n+1)(2n+1)/6
N = 24
Sum = 24*25*49/6 = 4900
N = 24
Sum = 24*25*49/6 = 4900
A number when divided by 143 leaves 31 as remainder. What will be the remainder
when the same number is divided by 13 ?- a)0
- b)1
- c)3
- d)5
- e)None of these
Correct answer is option 'D'. Can you explain this answer?
A number when divided by 143 leaves 31 as remainder. What will be the remainder
when the same number is divided by 13 ?
when the same number is divided by 13 ?
a)
0
b)
1
c)
3
d)
5
e)
None of these
|
Abhishek answered |
Number is = x
x = divisor + remainder
x = 143 + 31
x = 174
when the same number is decided by 13
remainder= 174÷13
= 5 Ans.
x = divisor + remainder
x = 143 + 31
x = 174
when the same number is decided by 13
remainder= 174÷13
= 5 Ans.
N is the smallest number which when added to the 2000 makes the resulting number divisible by 12, 16, 18 and 21, Then the N is- a)11
- b)7
- c)9
- d)16
- e)None of these
Correct answer is option 'D'. Can you explain this answer?
N is the smallest number which when added to the 2000 makes the resulting number divisible by 12, 16, 18 and 21, Then the N is
a)
11
b)
7
c)
9
d)
16
e)
None of these
|
|
Preeti Khanna answered |
LCM of 12, 16, 18, 21 = 1008
1008*2 = 2016
N = 16
1008*2 = 2016
N = 16
Find the least number which must be subtracted from 103876 to make the obtained number divisible by 16.- a)5
- b)4
- c)3
- d)7
- e)9
Correct answer is option 'B'. Can you explain this answer?
Find the least number which must be subtracted from 103876 to make the obtained number divisible by 16.
a)
5
b)
4
c)
3
d)
7
e)
9
|
|
Target Study Academy answered |
- Divide 103876 by 16.
- The quotient is 6492 with a remainder of 4.
- To make 103876 divisible by 16, subtract the remainder.
- Therefore, subtract 4 from 103876.
- The resulting number, 103872, is divisible by 16.
Answer: b) 4
- The quotient is 6492 with a remainder of 4.
- To make 103876 divisible by 16, subtract the remainder.
- Therefore, subtract 4 from 103876.
- The resulting number, 103872, is divisible by 16.
Answer: b) 4
Two different numbers are divided by the same divisor and left remainder 11 and 17 respectively and when their sum was divided by the same divisor, remainder was 4. What is the divisor?- a)20
- b)24
- c)25
- d)26
- e)None of these
Correct answer is option 'D'. Can you explain this answer?
Two different numbers are divided by the same divisor and left remainder 11 and 17 respectively and when their sum was divided by the same divisor, remainder was 4. What is the divisor?
a)
20
b)
24
c)
25
d)
26
e)
None of these
|
Jatin Nambiar answered |
Let the divisor = D
so, first number = D*a + 11 and second number = D*b +17
so sum of numbers = D*(a + b) + 28
given that remainder is 4 so, the number is 24
so, first number = D*a + 11 and second number = D*b +17
so sum of numbers = D*(a + b) + 28
given that remainder is 4 so, the number is 24
The number of prime factors of 510510- a)4
- b)5
- c)6
- d)7
Correct answer is option 'D'. Can you explain this answer?
The number of prime factors of 510510
a)
4
b)
5
c)
6
d)
7
|
|
Faizan Khan answered |
2*3*5*7*11*13*17 = 510510
x+(1/x) = 2, then find the value of x + (-1/x)
- a)2
- b)1
- c)0
- d)3
Correct answer is option 'C'. Can you explain this answer?
x+(1/x) = 2, then find the value of x + (-1/x)
a)
2
b)
1
c)
0
d)
3
|
|
Kishore Kumar answered |
The answer given above is INCORRECT .
X+(1/X) = 2 ;
(X^2+ 1)/ X = 2 ;
X^2+1 = 2X ;
X^2 - 2X + 1= 0 ;
By factorisation method ,
X = 1 ;
Now substitute X= 1 in X +(-1/X) ;
we get , 1 - 1/1 = 0 ;
Therefore , X = 0 ;
X+(1/X) = 2 ;
(X^2+ 1)/ X = 2 ;
X^2+1 = 2X ;
X^2 - 2X + 1= 0 ;
By factorisation method ,
X = 1 ;
Now substitute X= 1 in X +(-1/X) ;
we get , 1 - 1/1 = 0 ;
Therefore , X = 0 ;
Find the 5 digit number, 5th digit is one fourth of the 3rd digit and one half of the 4th digit. 3rd digit is one half of the 1st digit. 2nd digit is 5 more than the 5th digit.- a)12786
- b)86421
- c)46218
- d)24675
Correct answer is option 'B'. Can you explain this answer?
Find the 5 digit number, 5th digit is one fourth of the 3rd digit and one half of the 4th digit. 3rd digit is one half of the 1st digit. 2nd digit is 5 more than the 5th digit.
a)
12786
b)
86421
c)
46218
d)
24675
|
|
Anaya Patel answered |
5th digit – 1
Second – 1+5 = 6
Third = 4
Four = 2
First = 4*2 = 8
Second – 1+5 = 6
Third = 4
Four = 2
First = 4*2 = 8
Which one cannot be the square of a natural number ?- a)2116
- b)2304
- c)2202
- d)2209
Correct answer is option 'C'. Can you explain this answer?
Which one cannot be the square of a natural number ?
a)
2116
b)
2304
c)
2202
d)
2209
|
Smiling Kids Foundation answered |
It is c because C can be divided by 2
Chapter doubts & questions for Number System - Mathematics for RRB NTPC / ASM 2025 is part of RRB NTPC/ASM/CA/TA exam preparation. The chapters have been prepared according to the RRB NTPC/ASM/CA/TA exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for RRB NTPC/ASM/CA/TA 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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