RRB NTPC - Averages (200 Questions with Explanation): Quantitative Aptitude Test

1.

The average of 24 numbers is zero. Of them, at the most how many may be greater than zero? 

   A.) 20
   B.) 21
   C.) 22
   D.) 23

Answer: Option 'D'

Average of 24 numbers is = 0
Therefore sum of all 24 numbers = 0
It is quite possible that 23 of these numbers may be positive and if their sum is "a" then 24th number is "(-a)"

2.

The average temperature for Monday, Tuesday and Wednesday was 41 c. the average temperature for Tuesday, Wednesday and Thursday was 42 c. If the temperature on Thursday be 43 c, what was the temperature on Monday?

   A.) 41 c
   B.) 39 c
   C.) 40 c
   D.) 42 c

Answer: Option 'C'

Answer: Option 'C'

3.

The average weight of a class having 14 students is 44 kg. Find the total weight of the class.

   A.) 606
   B.) 616
   C.) 626
   D.) 636

Answer: Option 'B'

Solution is
Average = Total Quantity / No. of Quantity
Total quantity = Avg x No. of Quantity

Total quantity = 14 x 44
= 616
Answer is 616

4.

Six years ago, the ratio of the ages of Kunal and Sagar was 6 : 5. Four years hence, the ratio of their ages will be 11 : 10. What is Sagar's age at present?  

   A.) 16 years
   B.) 20 years
   C.) 18 years
   D.) Cannot be determined

Answer: Option 'A'

Given, Six years ago, the ratio of ages ofKunal and Sagar = 6 : 5
Thus, the ages of Kunal and Sagar 6 years ago be 6x and 5x years respectively.
Then, the present age of Kunal = 6x + 6
the present age of Sagar = 5x + 6
Given,Four years hence, the ratio of their ages will be 11 : 10
=> The age of Kunal after four years = 6x + 6 + 4 = 6x + 10
The age of Sagar after four years = 5x + 6 + 4 = 5x + 10
=>(6x + 10) / (5x + 10) = 11 / 10
=> 10 (6x + 10) = 11 (5x + 10)
=> 60x + 100 = 55x + 110
=> 60x - 55x = 110 - 100
=> 5x = 10
=> x = 2
Thus, present age of Sagar =5x + 6
= 5(2) + 6
= 10 + 6
16 years

5.

In the first 25 overs of a cricket game, the run rate was only 5.6. What should be the run rate in the remaining 25 overs to reach the target of 280 runs?

   A.) 6.2
   B.) 6.7
   C.) 5.6
   D.) 5

Answer: Option 'C'

Required Run rate = ( 280 - ( 5.6 x 25 ) )/ (25) = ( 140) /(25) = 5.6

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