### The mean of 9 observation is 16. One more observation is included and the new mean becomes 17. The 10th observation is :

A. 9 B. 16 C. 26 D. 30 Answer: Option C

### Solution(By Apex Team)

According to the question mean of 9 observations is = 16 Sum of all observations is = 16 × 9 = 144 When one more observation included the new mean = 17 Sum of 10 observations = 10 × 17 = 170 ∴ 10th observation = 170 – 144 = 26

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