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.
