Let x points make the game, then A has x points while B and C has (x – 15) and (x – 22) points respectively and also if B has x points then C has (x – 10) points. Applying chain rule, x . x (x – 22) = x (x – 15) (x – 10) ⇒ x2 – 22x = x2 – 25x + 150 ⇒ 3x = 150 ⇒ x = 50