Correct Answer - Option 2 : 72 kg
Given:
Average weight of 5 boys = 60 kg
Average weight of boys increases when a new boy joins them.
Formula used:
Sum of weight = Average weight × Number of persons
Calculation:
Let the weight of the new boy be x.
According to the question,
Average age of five boys = 60 kg
So, Sum of weight of five boys = 60 × 5
⇒ 300 kg
After the new boy joins them, then
New Average = (Sum of weight of five boys + Weight of new boy)/6
⇒ 60 + 2 = (300 + x)/6
⇒ 62 × 6 = 300 + x
⇒ x = 372 – 300
⇒ x = 72 kg
∴ The weight of the new boy is 72 kg.
