# Aptitude Average Questions for SSC CGL, CHSL, MTS Exam Pdf - 1

Question: 1

A student was asked to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What should be the number in place of x?

(A) 3

(B) 4

(C) 7

(D) 11

Ans: C

Clearly, we have

\$\$({3 + 11 + 7 + 9 + 15 + 13 + 8 + 19 + 17 + 21 + 14 + x}/{12})\$\$ = 12

or 137 + x = 144

or x = 144 - 137 = 7

Question: 2

The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then

(A) 2x = y + z

(B) x = y + z

(C) x = 2y + 2z

(D) None of these

Ans: A

Clearly, we have: x = \$\$({3y + 3z} / {6})\$\$ or 2x = y + z.

Question: 3

The average expenditure of a man for the first five month is Rs.3600 and for next seven months it is Rs.3900. If he saves Rs.8700 during the year, his average income per month is

(A) 4000

(B) 4500

(C) 5000

(D) 5500

Ans: B

Total expenditure for the first five months

= 5 × 3600 = Rs.18000

Total expenditure for the next seven months

= 7 × 3900 = Rs.27300

Savings = Rs.8700

Total income during the year

= 18000 + 27300 + 8700 = Rs.54,000

Average income per month = \$\${54000}/{12}\$\$ = Rs.4500.

Question: 4

The average age of a class of 65 boys was 14 years, the average age of 20 of them was 14 years, and that of another 15 was 12 years. Find the average age of the remaining boys.

(A) 13 years

(B) 15 years

(C) 17 years

(D) 19 years

Ans: B

Required average

= \$\${(65 × 14) - (20 × 14 + 15 × 12)} / {65 – (20 + 15)}\$\$ = \$\${910 - 460} / {30}\$\$ = \$\${450}/{30}\$\$ = 15.

Question: 5

A, B, C and D are four consecutive odd numbers and their average is 42. What is the product of B and D?

(A) 1677

(B) 1845

(C) 1860

(D) 1890

Ans: B

Since the numbers are consecutive, they should be equidistant from the average. i.e., 42.

Hence, the numbers are 39, 4, 43 and 45.

Product of B and D = 41 × 45 = 1845.

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