Question

The average weight of 6 boys gets increased by 5kg if a boy with weight 20kg is replaced by a new boy,what is the weight of the new boy?​

Answer 1

the answers is given above

Answer 2

Given,

Weight of old 6th boy = 20 kg

The average weight is increased by 5 kilograms when we add the new 6th boy.

To find,

The weight of the new 6th boy.

Solution,

Let, the average of the weight of 6 boys with the old 6th boy = x kg

So, the sum of the weight of the 6 boys with the old 6th boy = (6×x) = 6x kg

After removing the the old 6th boy, the sum of the weight of the 5 boys = (6x-20) kg

Let, the weight of the new boy = y kg

Sum of weight of the 6 boys with new 6th boy = 6x-20+y kg

Average of the weight of the 6 boys with new 6th boy = (6x-20+y)/6 kg

According to the data mentioned in the question,

(6x-20+y)/6 = x+5

6x-20+y = 6x+30

-20+y = 30

y = 50

Hence, the weight of the new boy is 50 kilograms.