Question

The average age of P and Q is 30 years. If R were to replace P, the average would be 25 and if R were to replace Q, the average would be 26. What are the age of P, Q and R?

• A. 32, 28, 20
• B. 31, 29, 21
• C. 24, 25, 20
• D. 28, 25, 21

Answer 1

Answer:

B. 31, 29, 21

The average age of P and Q is 30 years. The total age of P and Q = 30 × 2 = 60 years. P + Q = 60 …………(i) R + Q = 50 …………(ii) P + R = 52 …………(iii) 2(P + Q + R) = 60 + 50 + 52 ⇒ P + Q + R = 162/2 = 81 ………..(iv) (P + Q + R) – (P + Q) = 81 – 60 ⇒ R = 21 (P + Q + R) – (R + Q) = 81 – 50 ⇒ P = 31 (P + Q + R) – (P + R) = 81 – 52 ⇒ Q = 29