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.**