Let x and y be the certain number of males and females. Then, by condition, x =
1
2
(y - 15) ⇒ 2x = y - 15 ⇒ 2x - y = - 15 ... (i) and 5 (x - 45) = y ⇒ 5x - y = 225 ... (ii) On subtracting Eq. (i) from Eq. (ii), we get 3x = 240 ⇒ x = 80 ∴ Number of males = 80