The ratio of the age of a father to that of his son is 5:2. If the product of their ages is 1000, then the father's age ( in yr) after 10 yr will be a

Options

A. 50
B. 60
C. 80
D. 100

Answer

B

Explanation

Let the father.s age = `5x y`
and his son.s age `= 2x y`
`therefore` Product of their age = `5x xx 2x = 1000 `
`implies 10x^2= 1000`
`implies x^2 = 1000/10`
`implies x = 10`
`therefore` Father.s age = `5x = 50 yr `
and son.s age = `2x = 20 yr `
After `10 yr`, father.s age = 50 + 10
`= 60 yr `