The average weight of P and his three friends is 55 kg. If P is 4 kg more than the average weight of his three friends, what is P's weight (in kg)?
The total weight of P and his three friends = 55 × 4 = 220 kg Let, the average weight of three friends = x So, the total weight of three friends = 3x The weight of P = x + 4 Then, (x + 4) + 3x = 220 ⇒ 4x + 4 = 220 ⇒ 4x = 220 - 4 = 216 ⇒ x = 216/4 = 54 ∴ P's weight = 4 + 54 = 58 kg