Question

1. The average weight of 6 boys gets increased by
5kg if a boy with weight 20 kg is replaced by a
new boy. What is the weight of new boy?
(a) 41 kg
(b) 50 kg
(c) 65 kg
(d) 49 kg​

Answer 1

Answer:

Correct solution:

There are 6 boys in a group.(given)

Let the original average weight was x. The new average is then (x+5).

Original group weight was 6x. New group weight is 6(x+5) = 6x + 30.

One boy of 20 kg left the group and new boy joins. Let the weight if new boy is y. .

So ( change in) group weight is 6x -20 + y.

Thus, 6x-20+y = 6x +30.. Solving for y,

y=30+20=50 kg. . the new boy weighs 50 kg.