### The average of seven numbers is 18. If one of the numbers is 17 and if it is replaced by 31, then the average becomes :

A. 21.5 B. 19.5 C. 20 D. 21 Answer: Option C

### Solution(By Apex Team)

According to the question, Actual number = 17 New number = 31 Difference = 31 – 17 = 14 Difference ’14’ effects the seven numbers $=\Large\frac{14}{7}$=2 ∵ Present average = 18 ∴ New average = 18 + 2 = 20

A. 20
B. 21
C. 28
D. 32

A. 18
B. 20
C. 24
D. 30

A. 10 years
B. 10.5 years
C. 11 years
D. 12 years