The maximum weight that an elevator can carry is 350 kg. Three men A, B and C enter into the elevator on the ground floor and their average weight is 84 kg. Another man D enters the elevator on the first floor. Now, the average weight of all 4 people in the elevator is 80 kg. At the second floor, A gets out of the elevator and E enters. E's weight is 3 kg more than D, and the present average weight of all 4 people in the elevator is 79 kg. What is A's weight?

The total weight of the four people on the first floor is 80 times 4, which equals 320 kg. When A leaves and E enters on the second floor, the new total weight becomes 79 times 4, equaling 316 kg. The total weight decreases by 4 kg, meaning A weighs 4 kg more than E. Since E is 3 kg heavier than D, A is 7 kg heavier than D. The total weight of A, B, and C is 84 times 3, or 252 kg, making D's weight 320 minus 252, which is 68 kg. Therefore, A weighs 68 plus 7, resulting in 75 kg.

• Thanks
• Wrong explanation