Question

. The ratio of ages of A, B, C is 5:7:12. If age of 'B' is more by two and a half years than age of ‘A’, then what was the age of 'C' two years before?
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Answer 1

Let 5 years ago age of A to B = 4x ∶ 5x

According to the question

⇒ (4x + 10)/(5x + 10) = 6/7

⇒ 7(4x + 10) = 6(5x + 10)

⇒ 28x + 70 = 30x + 60

⇒ 30x – 28x = 70 – 60

⇒ 2x = 10

⇒ x = 10/2 = 5

5 years ago, age of A = 4x = 4 × 5 = 20

Present age of A = 20 + 5 = 25 years

5 years ago, age of B = 5x = 5 × 5 = 25

Present age of B = 25 + 5 = 30

Present age of C = 30 – 10 = 20

Ratio of present age of A to C = 25 ∶ 20 = 5 ∶ 4