Given: Average age of Ram, Rena, Seema and Pinky = 40 years Ram’s age = 2 × Rena’s age Rena’s age = 2 × Seema’s age Pinky’s age = 20 years Concept: Average = Total sum/ Total persons Calculation : Sum of age of Ram, Rena, Seema and Pinky = 40 × 4 ⇒ 160 Sum of age of Ram, Rena and Seema = 160 — 20 ⇒ 140 Let Seema’s age = 1a ∴ Rena’s age = 2a ∴ Ram’s age = 4a 1a + 2a + 4a = 140 7a = 140 a = 20 ∴ Ram’s age = 4a ⇒ 4 × 20 ⇒ 80 years Age of Ram = 80 years