Question

The mean of 15 observation is 9. One more observation is included and the new mean becomes 12. Find the value of new observation.
1. 21
2. 23
3. 45
4. 57

Answer 1

Correct Answer - Option 4 : 57

Given

Mean of 15 observation = 9

Formula used

Average = (sum of all observation)/Number of observation

Calculation

Sum of 15 observation = 15 × 9

⇒135

Sum of 16 observation = 16 × 12

⇒192

Value of new observation = 192 - 135

⇒57

∴ Value of new observation is 57.