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.