Question
The average age of A and B is 19 years. If A is to be
replaced by C, the average would be 18 years. The average age of C and A is 20 years. Find the age of A.Solution
A + B = 2 × 19 = 38 yr B + C = 2 × 18 = 36 yr C + A = 2 × 20 = 40 yr On adding all three, 2 (A + B + C) = 38 + 36 + 40 = 114 ⇒ A + B + C = 57 ∴ A = (A + B + C) – (B + C) = 57 – 36 = 21 yr
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