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** ** **