Average Mcqs

The average weight of a group of boys is 30 kg. After a boy of weight 35 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally?

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The average weight of a group of boys is 30 kg. After a boy of weight 35 kg joins the group, the average weight of the group goes up by 1 kg. Find the number of boys in the group originally?

A. 4
B. 5
C. 6
D. 7
Explanation:
Let the number off boys in the group originally be x.
Total weight of the boys = 30x
After the boy weighing 35 kg joins the group, total weight of boys = 30x + 35
So 30x + 35 + 31(x + 1) = > x = 4

A salt manufacturing company produced a total of 5000 tonnes of salt in January of a particular year. Starting from February its production increased by 100 tonnes every month over the previous months until the end of the year. Find its average monthly production for that year?

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A salt manufacturing company produced a total of 5000 tonnes of salt in January of a particular year. Starting from February its production increased by 100 tonnes every month over the previous months until the end of the year. Find its average monthly production for that year?

A. 6060
B. 7070
C. 5550
D. 4440
Explanation:
Total production of salt by the company in that year = 5000 + 5100 + 5200 + …. + 6100 = 66600.
Average monthly production of salt for that year = 66600/12 = 5550

The average amount with a group of seven numbers is Rs. 20. If the newly joined member has Rs. 50 with him, what was the average amount with the group before his joining the group?

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The average amount with a group of seven numbers is Rs. 20. If the newly joined member has Rs. 50 with him, what was the average amount with the group before his joining the group?

A. Rs. 25
B. Rs. 18
C. Rs. 15
D. Rs. 22
Explanation:
Total members in the group = 7
Average amount = Rs. 20
Total amount with them = 7 * 20 = Rs. 140
One number has Rs. 50. So, the amount with remaining 6 people = 140 – 50 = Rs. 90
The average amount with them = 90/6 = Rs. 15

The sum of five numbers is 655. The average of the first two numbers is 85 and the third number is 125. Find the average of the two numbers?

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The sum of five numbers is 655. The average of the first two numbers is 85 and the third number is 125. Find the average of the two numbers?

A. 180
B. 170
C. 190
D. 175
Explanation:
Let the five numbers be P, Q, R, S and T.
=> P + Q + R + S + T = 655.
(P + Q)/2 = 85 and R = 125
P + Q = 170 and R = 125
P + Q + R = 295
S + T = 655 – (P + Q + R) = 360
Average of the last two numbers = (S + T)/2 = 180

The average age of a group of 10 persons was decreased by 3 years when one person, whose age was 42 years, was replaced by a new person. Find the age of the new person?

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The average age of a group of 10 persons was decreased by 3 years when one person, whose age was 42 years, was replaced by a new person. Find the age of the new person?

A. 22
B. 24
C. 12
D. 8
Explanation:
Initial average age of the 10 persons be P.
Age of the new person Q.
Sum of the ages of the initial 10 persons = 10P
New average = (P-3) 10(P-3) = 10P – 42 + Q => Q = 12

The average of the marks of 12 students in a class is 36. If the marks of each student are doubled, find the new average?

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The average of the marks of 12 students in a class is 36. If the marks of each student are doubled, find the new average?

A. 72
B. 45
C. 37
D. 79
Explanation:
Sum of the marks for the 12 students = 12 * 36 = 432. The marks of each student are doubled, the sum also will be doubled.
The new sum = 432 * 2 = 864. So, the new average = 864/12 = 72

The average of 35 numbers is 25. If each number is multiplied by 5, find the new average?

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The average of 35 numbers is 25. If each number is multiplied by 5, find the new average?

A. 125
B. 134
C. 170
D. 98
Sum of the 35 numbers = 35 * 25 = 875
If each number is multiplied by 5, the sum also gets multiplied by 5 and the average also gets multiplied by 5.
Thus, the new average = 25 * 5 = 125

The average salary of a person for the months of January, February, March and April is Rs.8000 and that for the months February, March, April and May is Rs.8500. If his salary for the month of May is Rs.6500, find his salary for the month of January?

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The average salary of a person for the months of January, February, March and April is Rs.8000 and that for the months February, March, April and May is Rs.8500. If his salary for the month of May is Rs.6500, find his salary for the month of January?

A. 3000
B. 2500
C. 4500
D. 5000
Sum of the salaries of the person for the months of January, February, March and April = 4 * 8000 = 32000 —-(1)
Sum of the salaries of the person for the months of February, March, April and May = 4 * 8500 = 34000 —-(2)
(2)-(1) i.e. May – Jan = 2000
Salary of May is Rs.6500
Salary of January = Rs.4500