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The average monthly expenditure of Mr.Ravi’s family for the first three months is Rs 2,750, for the next three months is Rs 2,940 and for the last three months Rs 3,150. If his family saves Rs 4980 for nine months, find the average monthly income of the family for the 9 months?
Answer – B. Rs. 3500 Explanation : Average monthly expenditure for 3 months = Rs. 2750 Total expenditure for 3 months = Rs 2750 x 3 = Rs. 8250 Average monthly expenditure for 3 months = Rs. 2940 Total expenditure for 3 months = Rs 2940 x 3 = Rs. 8820 Average monthly expenditure for 3 months = Rs. 3150 Total expenditure for 3 months = Rs 3150 x 3 = Rs. 9450 Total savings for 9 months = 4980 Average monthly income for 9 months = (8250 + 8820 + 9450 + 4980)/9 = 3500
The average age of a family of 8 members is 24 years. If the age of the youngest member be 6 years, the average age of the family at the birth of the youngest member was?
The average age of a family of 8 members : 24 years
Sum of ages of eight members:
=> 24*8 = 192
6 years ago their total age was :
=> 192  (6*8)
=> 192  48
=> 144
The average age of 7 members, 6 years ago:
=> 144/7
=> 20.57 years.
Mr. Ravi’s family has 10 males and a few females, the average monthly consumption of rice per head is 8 kg. If the average monthly consumption of rice per head be 10 kg in the case of males and 6 kg in the case of females, find the number of females in Ravi’s family?
Answer – D. 10 Explanation: Let number of females be x. (10*10+x*6)/(10+x) = 8 => x = 10
In a famous hotel the rooms were numbered from 201 to 230, each room gives an earning of Rs. 5000 for the first fifteen days of a month and for the latter half, Rs. 3000 per room. Find the average income per room per day over the month. (September)?
Answer – C. 4000 Explanation: Total number of rooms = 29 Average = [(5000 * 30 * 15) + (3000 * 30 * 15)]/(30*30) Average earning per room = 4000
In a famous hotel, the rooms are numbered from 101 to 130 on the first floor, 201 to 220 on the second floor and 301 to 330 on the third floor. In the month of September, the room occupancy was 50% on the first floor, 80% on the second floor and 40% on the third floor. If it is also known that the room charges are Rs 200, Rs. 250 and Rs. 300 on each of the floors respectively, then find the average income per room in the hotel for the month of September?
Total number of rooms in first, second and third floor = 30, 20, 30
Occupied rooms in first, second and third floor = 15, 16, 12
Average income = (15 * 200 + 16 * 250 + 12 * 300)/ 80 = Rs. 132.5
There were 46 students in a Boys hostel. Due to the admission of eight new students the expenses of the hostel mess were increased by Rs.42 per day while the average expenditure per head diminished by Rs 1. What was the original expenditure of the hostel mess?
Answer – E. Rs.552 Explanation: 54*(x−1)−46*x = 42 8x = 96 x = 12 Original total expenditure: 46*x = 46*12 = Rs.552
The average salary of the entire staff in a office is Rs 250 per month. The average salary of officers is Rs 520 and that of nonofficers is Rs. 200. If the number of officers is 15, then find the number of non–officers in the office
Answer – B. 81 Explanation: Let the required number of non–officers = x 200x + 520 x 15 = 250 ( 15 + x ) 250x – 200x = 520 * 15 – 250 x 15 50x = 4050 x = 81
Mr.Suresh’s average monthly expenditure for the first four months of the year was Rs.260 For the next five months,the average monthly expenditure was Rs.40 more than what it was during the first four months. If he spent Rs.560 in all during the remaining three months of the year, Find what percentage of his annual income of Rs.5000 did he save in the year?
Answer – C. 38% Explanation: Suresh’s average monthly expenditure for the first four months of the year = Rs.260. 260 * 4 = Rs. 1040 For the next five months,the average monthly expenditure was Rs.40 more than what it was during the first four months. He spent 260 + 40 for one month In 5 months he spent 300 * 5 = 1500 He spent Rs.560 in all during the remaining three months of the year.
Total expenditure = 1040 + 1500 + 560 = 3100 Savings = 50003100 = 1900 % savings = 1900/5000 * 100 = 38%
The average age of a group of persons going for tour to Shimla is 22 years. 25 new persons with an average age of 10 years join the group and their average age becomes 12 years. The number of persons initially going for tour is?
Answer – D. 5 Explanation: Initial number of persons = x = 22x + 25 * 10 – 12(x + 25) = 22x + 250 – 12x – 300 10x = 50 x = 5
In English exam, the average of Class “A” was found to be “x” marks. After deducting a computational error, the average marks of 100 candidates got reduced from 74 to 54. The average thus came down by 25 marks. The total numbers of candidates who took the English exam were?
Answer – C. 80 Explanation: (74 – 54) * 100 = 25 * x x = 20 * 100 / 25 = 80
The average age of a husband and his wife was 25 years when they were married 7 years ago. Now the average age of husband, wife and his son is 23 years. Find the age of son now.
Answer – 3.5yr Explanation : (h+w – 14)/2 = 25 H+w = 64 Now, (h+w+s)/3 = 23 S = 6964 = 5 years
The average of 10 reading is 25.5. In this the average of first three is 20 and the next four is 26. If the eight reading is 5 less than the night one and also 8 less than the tenth one, then find the eight reading?
Answer – 3.26 Explanation : sum of all ten reading = 255 sum of first three = 60 and sum of next 4 = 104.
Sum of 8^{th} , 9^{th} and 10^{th} reading = 91 = 3*x + 13 X = 26
The average of first and second number is 25 more than the average off the second and third number. Find the difference between the first and the third number
Answer – 4.50 Explanation : (a+b)/2 = 25 + (b+c/2)
In a hostel there are 30 students and if the number of students increased by 5 then the expense is increased by 40 per day. But the average expenditure diminishes by 3. Find the original expenditure.
Answer – 2.870 Explanation : Let average expenditure be P. (30*P + 40)/35 = P3
P = 29. So expenditure = 29*30 = 870
The average age of a class is 19 years. While the average age of boys is 20 and the average age of girls is 17. If the number of boys is 20 then find the number of girls in the class
Answer – 1.10 Explanation : Average of class = 19 = Sum/(b+g) sum (girls) = g*17 sum (boys) = b*20 19b + 19g = 17g + 20b 2g = b = 20. So girls = 10
Three years back, the average age of 5 members family is 17 years. After a child is born and now the average age of the family remains same. What is the present age of the child?
Three back total age of 5 members = 17 * 5 = 85 years.
Total present age of 5 members = 85 + 3 * 5 = 100 years.
Now, a child born, average age reamin sam.
Average of 6 people = 17
Toatl age of 6 people = 17 * 6 = 102 years.
Age of child = 102  100 = 2 years
The average height of 50 students in a class is 165cm. On a particular day, three students P,Q and R are absent, so the average of the remaining students becomes 163cm. If the height of P and Q is equal and height of R is 2 cm less than P, then find the height of P.
Answer – 3.197 Explanation : sum of height (50) = 50*165 = 8250 sum of height (47) = 47*163 = 7661 sum of the height of P, Q and R = 82507661 = 589 P+P+P2 = 589 (as height of P is equal to Q and height of R = P 2) P = 197
The average age of a committee of 12 members is 48 years. A member of the committee age 62 retired and in place of him a new person aged 26 joined the committee. Find the new average of the committee.
Answer – 2.45 Explanation : Total age of committee = 48*12 new total age of committee = (48*12 – 62 + 26)/12 = 45
The average weight of 12 people gets increased by 3.5kg when a person weighs 56 kg got replaced by another man. Find the weight of the new man
Answer – 4.98kg Explanation : Let the weight of new man is x kg. (12p – 56 + x)/12 = p + 3.5 [12p is the total weight of 12 people] X = 98kg
In an examination the average marks of risha is 74. If she got 16 more marks in hindi and 20 more marks in English then her average would have been 78. Find the total number of subjects he studied?
Answer – 3.9 Explanation : Let total subjects are P.
Then, (74p + 20 + 16)/p = 78 So, P = 9
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