Eighteen years ago, the ratio of A's age to B's age was 8: 13. Their present ratios are 5: 7. What is the present age of A?

Options

A. (a) 50 years
B. (b) 70 years
C. (c) 40 years
D. (d) 60 years

Answer

A

Explanation

`A/B = 5/7`
` (A - 18)/(B - 18) = 8/13`
` rArr (A - 18) xx 13 = 8 (B - 18)`
` rArr 13A - 234 = 8B - 144`
` rArr 13A - 234 = 8 xx (7A)/(5) - 144`
` rArr 65A - 56A = 90 xx 5`
` rArr 9A = 90 xx 5`
`rArr A = 10 xx 5 = 50 ` वर्ष