A boy was asked of his age by his friend.  The boy said, the number you get when you subtract 15 times my age from twice the square of my age will be thrice your age.  If the friend's age is 14, then the age of the boy is?

14

Assume age of boy = x

ATQ,

⇒ 2x² - 25x = 42

⇒ x (2x - 25) = 42

⇒ 14 (2 x 14 - 25) = 42 ⇒ 42 = 42      (check from option)

⇒ Hence, The age of boy = 14 years