7 people spent Rs. 18 each on a group project and the 8th person spent Rs. 7 less than the average expenditure of all 8 persons. What is the total mon

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7 people spent Rs. 18 each on a group project and the 8th person spent Rs. 7 less than the average expenditure of all 8 persons. What is the total money spent by them?
1. Rs. 132
2. Rs. 126
3. Rs. 129
4. Rs. 136
5. Rs. 160

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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