Question

In a class, there are 40boys and their averageage is 16 yr. 1 boy , aged 17 yr,
Leave the class and another joining, the
average becomes 15.875 yr. The age of new boy is

Answer 1

Answer:

12 Years

Step-by-step explanation:

Number of boys in class = 40

Average age of 40 boys = 16 Years

Total age of boys = 40 × 16 = 640 Years

17 Year age boy left so Age of 39 boys = 640 - 17 = 623 Years

One more boy joined

let say his age = x Years

so new total age of 40 boys = 623 + x Years

New Average age of 40 boys = 15.875 years

40 × 15.875 = 623 + x

635 = 623 + x

x = 635 - 623

x = 12 Years

Age of new boy joining = 12 Years