Multiple choice

7 years ago age of father was 1.75 times of the age of his son. 9 years hence his age becomes 1.5 times of the age of his son. Find the ratio of their present ages?

  1. 23 : 15

  2. 21 : 13

  3. 8 : 5

  4. Can not be determined

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let present ages be F (father) and S (son). 7 years ago: F-7 = 1.75(S-7). 9 years hence: F+9 = 1.5(S+9). Expanding: F-7 = 1.75S - 12.25, so F = 1.75S - 5.25. And F+9 = 1.5S + 13.5, so F = 1.5S + 4.5. Equating: 1.75S - 5.25 = 1.5S + 4.5, giving 0.25S = 9.75, S = 39. Then F = 1.5(39) + 4.5 = 63. Present ratio F:S = 63:39 = 21:13. Option B is correct. Key distractors: A (23:15) is close but incorrect, C (8:5) might come from calculation errors.

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