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

21.

If the average age of six numbers is 30. If one is excluded. The average become 25. The excluded number is:

A.) 54
B.) 55
C.) 53
D.) 45

22.

If the average age of six numbers is 30. If one is excluded. The average become 25. The excluded number is:

A.) 54
B.) 55
C.) 53
D.) 45

23.

Of the three numbers whose average is 45, the first is half of the sum of the others. The first number is:

A.) 45
B.) 51
C.) 59
D.) 49

45

24.

Of the three numbers whose average is 45, the first is half of the sum of the others. The first number is:

A.) 45
B.) 51
C.) 59
D.) 49

45

25.

The average age of father and his two sons is 27 Years. Five years ago, the average age of the two sons was 12 Years. If the difference between the ages of the two sons is four years, what is the present age of the father?

A.) 42
B.) 47
C.) 48
D.) 49

The total present age of father and two sons is 3S27 = 81 yrs
The total present age of sons is (12+5) X 2 = 34Years
so, present age of father is 81 - 34 = 47 yrs

26.

The average age of father and his two sons is 27 Years. Five years ago, the average age of the two sons was 12 Years. If the difference between the ages of the two sons is four years, what is the present age of the father?

A.) 42
B.) 47
C.) 48
D.) 49

The total present age of father and two sons is 3S27 = 81 yrs
The total present age of sons is (12+5) X 2 = 34Years
so, present age of father is 81 - 34 = 47 yrs

27.

There were 45 students in a hostel, if the numbers of students increased by 7, the expenses of the mess were increased by Rs. 39 per day while the average expenditure per head diminished by Re.1. What is the original expenditure of the mess?

A.) Rs. 562
B.) Rs. 624
C.) Rs. 1950
D.) Rs. 585

Let the original expenditure be Rs.x
Original average expenditure = X/45
New average expenditure = (x+39)/52
So (x/45) - ((x+39) / 52) = 1  so x = 585
so, original expenditure is Rs 585

28.

There were 45 students in a hostel, if the numbers of students increased by 7, the expenses of the mess were increased by Rs. 39 per day while the average expenditure per head diminished by Re.1. What is the original expenditure of the mess?

A.) Rs. 562
B.) Rs. 624
C.) Rs. 1950
D.) Rs. 585

Let the original expenditure be Rs.x
Original average expenditure = X/45
New average expenditure = (x+39)/52
So (x/45) - ((x+39) / 52) = 1  so x = 585
so, original expenditure is Rs 585

29.

Of three numbers, the third is twice the second and the second is 4 times the first. If their average is 78, the smallest of the three numbers is:

A.) 15
B.) 21
C.) 17
D.) 18

Let first number be x.
So,2nd no. = 4x & 3rd no.=8x.
So,x+4x+8x=78 × 3 = 234.
13x = 234
x = 234/13
Hence,smallest Number x=18.

30.

Of three numbers, the third is twice the second and the second is 4 times the first. If their average is 78, the smallest of the three numbers is:

A.) 15
B.) 21
C.) 17
D.) 18

Let first number be x.
So,2nd no. = 4x & 3rd no.=8x.
So,x+4x+8x=78 × 3 = 234.
13x = 234
x = 234/13
Hence,smallest Number x=18.