Averages (200 Questions with Explanation): Quantitative Aptitude Test

1.

The average age of a group of 10 students was 26. The average age increased by 1 years when two new students joined the group. What is the average age of the two new students who joined the group?

   A.) 22
   B.) 32
   C.) 21
   D.) 41

Answer: Option 'B'

The average age of a group of 10 students is 26.
Therefore, the sum of the ages of all 10 of them
= 10 × 26
= 260
When two students joins the group, the average increase by 1.
New Average = 27
Now there are 12 students Therefore, sum of all the ages of 12 students
= 12 × 27
= 324
Therefore, the sum of the ages of two students who joined
= 324 - 260
= 64
And the average age of these two students
= 64 / 2
= 32.

2.

The average weight of 8 persons increases by 1.5 kg when a person weighting 65 kg is replaced by a new person. What could be the weight of the new person?

   A.) 55
   B.) 66
   C.) 77
   D.) 88

Answer: Option 'C'

Let the average weight of 8 persons be 'x' kg
and the weight of the new person be 'y' kg
so, (8x - 65 + y) / 8 = x+1.5 => y = 65 + 8 * 1.5 = 77 kgs
Weight of the new person = 77 kgs.

3.

In a class of 23, the overall weight of the students is 1024. Can you find the average weight of students in the class?

   A.) 48.97
   B.) 46.75
   C.) 44.52
   D.) 42.29

Answer: Option 'C'

Use the below formula to find the average weight of the class Average Weight = ( Total Weight of Class / Total Number of Students) Average Weight = ( 1024/23) = 44.52

4.

In the first 30 overs of a cricket game, the run rate was only 7. What should be the run rate in the remaining 20 overs to reach the target of 325 runs. ?

   A.) 7.75
   B.) 5.15
   C.) 6.75
   D.) 5.75

Answer: Option 'D'

Required Run rate = ( 325 - ( 7 x 30 ) )/ (20) = ( 115) /(20) = 5.75

5.

In a class of 17, the overall weight of the students is 1024. Can you find the average weight of students in the class?

   A.) 60.24
   B.) 63.25
   C.) 66.26
   D.) 57.23

Answer: Option 'A'

Use the below formula to find the average weight of the class Average Weight = ( Total Weight of Class / Total Number of Students) Average Weight = ( 1024/17) = 60.24

6.

Total Marks obtained by a class is 1632 and the average score of the class is 68. Find the Total students in the class? 

   A.) 22
   B.) 24
   C.) 26
   D.) 28

Answer: Option 'B'

Use the below formula to find the Total, when Average and Total No. of Students is provided.
Formula: Total no of students = Total Marks / Average Marks
Total No. of students = ( 1632 / 68) = 24

7.

In the first 25 overs of a cricket game, the run rate was only 2.2. What should be the run rate in the remaining 25 overs to reach the target of 225 runs. ?

   A.) 7.5
   B.) 6.8
   C.) 5.8
   D.) 12.3

Answer: Option 'B'

"Required Run rate = ( 225 - ( 2.2 x 25 ) )/ (25) = ( 170) /(25) = 6.8 "

8.

Total marks obtained by a class is 720 and the average score of the class is 72. Find the total number of students in the class? 

   A.) 11
   B.) 10
   C.) 12
   D.) 13

Answer: Option 'B'

Total number of students = Total Marks / Average Marks
Total No. of students = (720 / 72) = 10

9.

Average of 13 results is 65. If the average of first six results is 61 and average of last six results is 59 Then find the seventh result?

   A.) 115
   B.) 135
   C.) 125
   D.) 105

Answer: Option 'C'

125

10.

In a class of 17, the overall weight of the students is 743. Can you find the average weight of students in the class?

   A.) 43.71
   B.) 41.52
   C.) 45.9
   D.) 48.08

Answer: Option 'A'

Use the below formula to find the average weight of the class Average Weight = ( Total Weight of Class / Total Number of Students) Average Weight = ( 743/17) = 43.71

11.

Total Marks obtained by a class is 1155 and the average score of the class is 55. Find the Total students in the class? 

   A.) 19
   B.) 20
   C.) 22
   D.) 21

Answer: Option 'D'

Use the below formula to find the Total, when Average and Total No. of Students is provided
Total no. of students = Total Marks / Average Marks
Total No. of students = (1155 / 55) = 21

12.

A particular student has scored an average marks of 69.25 in all his 55 subjects. Find the Total Score he has obtained in all his subjects?

   A.) 3999.19
   B.) 3808.75
   C.) 4189.63
   D.) 3618.31

Answer: Option 'B'

Use the below formula to find the Total, when Average and Total No. of Students is provided Total = Average * Total Students/People Total = Average * Total Number of Students) Average Weight = ( 69.25 x 55) = 3808.75

13.

The average age of a group of 10 students was 10. The average age increased by 1 years when two new students joined the group. What is the average age of the two new students who joined the group? 

   A.) 8
   B.) 16
   C.) 18
   D.) 21

Answer: Option 'B'

The average age of a group of 10 students is 10.
Therefore, the sum of the ages of all 10 of them = 10 * 10 = 100
When two students joins the group, the average increase by 1.
New Average = 11
Now there are 12 students
Therefore, sum of all the ages of 12 students = 132
Therefore, the sum of the ages of two students who joined = 132 - 100 = 32
And the average age of these two students = 16

14.

There were 20 students in a particular Class. The class teacher knows the overall height of all the students in the class is 1300. Can you find the average height of students in the class?

   A.) 65
   B.) 71.5
   C.) 68.25
   D.) 61.75

Answer: Option 'A'

Use the below formula to find the average height of students in the class Average Height = ( Total Height of all students in the Class / Total Number of Students) Average Height = ( 1300/20) = 65

15.

In the first 30 overs of a cricket game, the run rate was only 7. What should be the run rate in the remaining 20 overs to reach the target of 325 runs. ?

   A.) 6.3
   B.) 5.8
   C.) 9.4
   D.) 4.9

Answer: Option 'B'

5.8

16.

The average temperature for Monday, Tuesday and Wednesday is 36.30 C. The average temperature for Tuesday, Wednesday and Thursday is 36.70 C. If Monday's temperature recorded as 390 C, find the Thursday's temperature ?

   A.) 40.2º C
   B.) 40.4º C
   C.) 40.5º C
   D.) 41.2º C

Answer: Option 'A'

Mon + Tue + Wed Temperature = 3X36.3 = 108.9
Given, Monday's temperature = 39º C
=> Tue + wed Temperature = 108.9 - 39 = 69.9
Given, Tue + wed + Thu temperature = 3 X 36.7 = 110.1
So, Thursday's temperature = 110.1 - 69.9 = 40.2º C

17.

The sum of ages of 5 children born at the intervals of 3 years each is 50 years. What is the age of the youngest child?  

   A.) 4 years
   B.) 8 years
   C.) 10 years
   D.) 5 years

Answer: Option 'A'

Let the ages of children be x, (x + 3), (x + 6), (x + 9) and (x + 12) years.
Then, x + (x + 3) + (x + 6) + (x + 9) + (x + 12) = 50
5x = 20
x = 4.
Age of the youngest child = x = 4 years.

18.

The average age of a group of 10 students was 14. The average age increased by 1 years when two new students joined the group. What is the average age of the two new students who joined the group?

   A.) 20
   B.) 21
   C.) 21.5
   D.) 22

Answer: Option 'A'

The average age of a group of 10 students is 14.
Therefore, the sum of the ages of all 10 of them = 10 * 14 = 140
When two students joins the group, the average increase by 1. New Average = 15
Now there are 12 students Therefore, sum of all the ages of 12 students = 15 x 12 = 180
Therefore, the sum of the ages of two students who joined = 180 - 140 = 40
And the average age of these two students = 20

19.

The average weight of 16 students in a class is 36 kg. Find the total weight of the class.

   A.) 526
   B.) 496
   C.) 576
   D.) 556

Answer: Option 'C'

Average = Total Quantity / No. of Quantity Total quantity = Avg x No. of Quantity Total quantity = 16 x 36 = 576

20.

A particular student has scored an average marks of 69.25 in all his 33 subjects. Find the Total Score he has obtained in all his subjects?

   A.) 2513.78
   B.) 2399.51
   C.) 2170.99
   D.) 2285.25

Answer: Option 'D'

Use the below formula to find the Total, when Average and Total No. of Students is provided Total = Average * Total Students/People Total = Average * Total Number of Students) Average Weight = ( 69.25 x 33) = 2285.25

21.

A man spends Rs. 1600 per month on an average for the first three months, Rs 1550 for next four months and Rs. 1800 per month for the last five months and saves Rs . 5200 a year. What is his average monthly income (in Rs.)?

   A.) 2510
   B.) 2100
   C.) 2684
   D.) 2110

Answer: Option 'B'

Total expenditure for the first 3 months = 3 × 1600 = 4800
Total expenditure for 4 months = 4 × 1550 = 6200
Total expenditure for 5 months = 5 × 1800 = 9000
Total expenditure and saving (which is income for one year) = 4800 + 6200 + 9000 + 5200 = Rs. 25200
So, Average monthly income = 25200/12 = Rs. 2100

22.

There were 22 students in a particular Class. The class teacher knows the overall height of all the students in the class is 1200. Can you find the average height of students in the class?

   A.) 54.55
   B.) 57.28
   C.) 60.01
   D.) 51.82

Answer: Option 'A'

Use the below formula to find the average height of students in the class Average Height = ( Total Height of all students in the Class / Total Number of Students) Average Height = ( 1200/22) = 54.55

23.

The average of 18 numbers is zero. Of them, at the most how many may be greater than zero?

   A.) 18
   B.) 19
   C.) 17
   D.) 15

Answer: Option 'C'

Average of 18 numbers is = 0 Therefore sum of all 18 numbers = 0
It is quite possible that 17 of these numbers may be positive and if their sum is "a" then 18th number is "(-a)"

24.

In a class of 27, the overall weight of the students is 997. Can you find the average weight of students in the class? 

   A.) 36.93
   B.) 38.78
   C.) 40.62
   D.) 35.08

Answer: Option 'A'

Use the below formula to find the average weight of the class
Average Weight = (Total Weight of Class / Total Number of Students)
=>Average Weight = (997/27) = 36.93

25.

A father said to his son, "I was as old as you are at the present at the time of your birth". If the father's age is 38 years now, the son's age five years back was:

   A.) 14 years
   B.) 19 years
   C.) 33 years
   D.) 38 years

Answer: Option 'A'

Let the son's present age be x years. Then, (38 - x) = x => 2x = 38. => x = 19. Therefore, Son's age 5 years back (19 - 5) = 14 years.


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