A is twice as old as B, ten years ago. If A was four times as old as B, their present ages are ……………

Correct option is (B) 30 and 15

Let A's present age be x years and B's present age be y years.

Since, A is twice as old as B.

\(\therefore\) x = 2y              __________(1)

10 years ages, A's age = (x - 10) years

& B's age = (y - 10) years

Given that 10 years ago, A was four times as old as B.

\(\therefore\) x - 10 = 4 (y - 10)

\(\Rightarrow\) 2y - 10 = 4y - 40    (From (1))

\(\Rightarrow\) 4y - 2y = 40 - 10

\(\Rightarrow\) 2y = 30

\(\Rightarrow\) y = \(\frac{30}2\) = 15

\(\therefore\) x = 2 \(\times\) 15 = 30     (From (1))

Hence, their present ages are 30 and 15 years.

Correct option is B) 30 and 15