The sum of the ages of father and a son presently is 70 years. After 10 years, the son's age is exactly half that of the father. What are their ages now?

Options

A. 45 yr,25 yr
B. 50 yr, 20 yr
C. 47 yr, 23 yr
D. 50 yr, 25 yr

Answer

B

Explanation

Let present age of son `= xy`
Then, present age of father = `y yr `According to the question,
`x +y = 70 " " ...(i)`
Also, after 10 yr.
`implies 2(x + 10) = y + 10`
`2x + 20 = y + 10`
`2x - y=-10 " " ...(ii)`
From Eqs. (i) and (ii).
`x = 20 yr and y = 50 yr`