35 employees collected money for a donation, and the average contribution was Rs 100. Later their boss also contributed some money, and the average contribution became Rs 115. How much did the boss contribute?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Rs 640
The total collected is the average multiplied by the number of contributors. The boss’s share is the new total minus the old total.
Total from the 35 employees \(=35\times100=\) Rs 3500
Total after the boss joined (36 people) \(=36\times115=\) Rs 4140
Contribution of the boss \(=4140-3500=\) Rs 640
The boss contributed Rs 640.