35 employees collected money for donation. The average contribution was Rs.100 . Later on, their boss also contributed some money. Now the average contribution is Rs.115 . What is the contribution of boss ?
Answer & explanation
Correct answer: option 2
Total donation : 35 × 100 = 3500
Total donation including boss: 36 × 115 = 4140
Donation given by boss = 4140 - 3500 = Rs.640