Test: Average- 1

Average =   (76 + 65 + 82 + 67 + 85 )/ 5 = 375/5   =  75.

So, the correct option is 'A'

Let the five consecutive even numbers be x,
x + 2, x + 4, x + 6 and x + 8 respectively.
According to the question,
x + x + 2 + x + 4 + x + 6 + x + 8 = 5 × 52

B = x + 2 = 48 + 2 = 50 and E = x + 8 = 48 + 8 = 56
 B × E = 50 × 56 = 2800

So, the correct option is 'D'

Total weight increased = (8 x 2.5) kg = 20 kg.

Weight of new person = (65 + 20) kg = 85 kg.

So, the correct option is 'C'

Let score of Rahul, Manish, Suresh, Ajay be r, m, s, a respectively 
Average score of Rahul, Manish & Suresh is 63
⇒ Total score of Rahul, Manish & Suresh = 3 x 63 = 189
⇒ r + m + s = 189  —  (i) 
Rahul's score is 15 less than Ajay and 10 more than Manish
r = a - 15 —(2)
r = m + 10 — (3) 
Ajay scored 30 marks more than the average score of Rahul, Manish & Suresh

⇒ 3a = r + m + s + 90 ----(4)
Using the value of r + m + s from (i) in (4)
3a = 189 + 90
a = 93 
Using the value of a in (2)
r = 93 - 15
r = 78 
Using the value of r in (i)
78 + m + 3 = 189
m + s = 111 
i.e., sum of Manish's and Suresh's score = 111

So, the correct option is 'B'

Let the numbers are x, x+2, x+4, x+6, then 

=>x+3=24=>x=21
So largest number is 21 + 6 = 27 

So, the correct option is 'B'

Let the numbers be A1, A2 , A3 , A4 , A5

► Average of 5 numbers = (A1 + A2 + A3 + A4 + A5) / 5 = 308

► Now A1 + A2 + A3 + A4 + A5 = 308 x 5 = 1540

► Also,A1 + A2 = 482.5 x 2 = 965

and A4 + A5 = 258.5 x 2 = 517 

► A3 = 1540 − 965 − 517 = 58

So, the correct option is 'C'

Summation of ages of 54 girls= 54*10= 540 since 18 is mistakely taken in place of 8 so total summation of ages of girls after correction= 540-18+8= 530 Now the actual average age of the girls = 530/54 =9.81

So,the correct option is 'B'

Sum of seven consecutive numbers x+(x+1)+(x+2)+(x+3)+(x+4)+(x+5)+(x+6)=175 7x+21=175
7x=154
x=22
First number will be 22 and consecutive series is 22, 23, 24, 25, 26, 27, 28

Sum of first and last number =22+28=50

So, the correct option is 'D'

The total marks of nine students = 9 × 63 = 567

Sum of the marks of three students = 78 + 69 + 48 = 195

Therefore, the sum of marks of the remaining six students= 567 – 195 = 372

Average marks of remaining six students = 372/6 = 62.

So, the correct option is 'E'

So, the correct option is 'A'

Age of the teacher = (25×15−24×14)years
(375−336) years= 39years

So, the correct option is 'C'

► The sum of the five numbers = 5 * 213 =1065

► The sum of the first two numbers = 2 * 233.5 = 467

► The sum of  the last two numbers = 542

► Then the sum of the four numbers = 467 + 542 =1009

► So, the third number will be = 1065 – 1009 = 56

So, the correct option is 'B'

Total weight increased = (8 * 1.5) kg = 12 kg.
Weight of new man = 65 + 12 = 77 kg

So, the correct option is 'D'

Here, n = 21, a = 64, b = 65 
Weight of teacher = n (b - a) + b 
= 21 (65 - 64) + 65 = 21 + 65 = 86 kg

So, the correct option is 'C'

Height of the teacher = (17 * 143) − (16 * 142) = 2431 - 2272 = 159 cm

So, the correct option is 'A'

Given that average is 54 kg for 15 girls.

(Sum of weight of 15 girls) / 15 = 54

Sum of weight of 15 girls = 15 x 54 = 810

Now weight of teacher is also added so the average becomes 54 + 1 kg = 55 kg

(Sum of weight of 15 girls + Weight of teacher ) / (15 girls + 1 teacher)  = New average = 55 (Given)

(810 + Weight of teacher ) / (16) = 55 + 1

810 + Weight of teacher = 16 (56)

Weight of teacher = 896 - 810 = 86 kg

So, the correct option is 'D'

2+4+6+8+10+12+14+16+18+20/10 = 110/10
=11

So, the correct option is 'A'

► The first 15 odd numbers are 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29

► The sum of first 15 odd numbers are 225

► Therefore mean is equal to 225/15=15

► Median =Middle value=15

So, the correct option is 'D'

Even numbers between 11 to 63
= 12,14,16,18,20,..........,62.
Clearly, this is a series of consecutive even numbers.

According to the formula,
Average of consecutive even numbers = (First number + Last number)/2 = (12 + 62)/2  = 74/2 

So, the correct option is 'D'

Let the numbers be x, x + 1, x + 2,  x + 3, x + 4, x + 5 and x + 6
Then [x + (x + 1) + (x + 2) + (x + 3) + (x + 4) + (x + 5) + (x + 6)] / 7 = 20.
⇒ 7x + 21 = 140
⇒ 7x = 119
⇒ x =17.

Latest number = x + 6 = 23.

So, the correct  option is 'C'