Question

The average of 7 numbers is 8. If a number is added to them, the average becomes 9. What is the number added accordingly?
1. 12
2. 11
3. 16
4. 14

Answer 1

Correct Answer - Option 3 : 16

Given:

The average of 7 number = 8 

The average of 8 number  = 9

Calculation:

The total sum of 7 number = 7 × 8 = 56 

The total sum of 8 number = 8 × 9 = 72

then,

The added number = total sum of 8 no.-  total sum of 7 no.

72 - 56 = 16

∴The added number is 16 .