(cl) Let the ages of P, Q and R be x, y and z yr, respectively. According to the question, x + 2 y + z = 59 ...(i) 3x + y + z = 68 ...(ii) x + 3y + 3z = 108 ...(iii) On multiplying Eq. (ii) by 3 and subtracting from Eq. (iii), we get 8x = 96 ⇒ x = 12 yr ∴ Age of P = 12yr