Correct Answer - Option 4 : Rs. 136
Given:
7 people's expenditure = Rs 18
8 the person's expenditure = average expenditure - 7
Formula used:
Average = sum of observations/total number of observations
Calculation:
Let the average expenditure be Rs x
So, 8th person's expenditure = x - 7
A.T.Q
(18 × 7 + x - 7)/8 = x
⇒ 126 + x - 7 = 8x
⇒ 7x = 119
⇒ x = 17
∴ Total expenditure = 17 × 8 = Rs 136
∴ The answer is Rs 136