Multiple choice

My grandmother was 9 times as old as me, 16 years ago. She would be 3 times of my age, 8 years from now. Eight years ago, what was the ratio of my age to that of my grandmother?

  1. 3: 8

  2. 1: 5

  3. 1: 2

  4. 2: 5

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

Let current ages be G (grandmother) and M (me). 16 years ago: G - 16 = 9(M - 16) → G = 9M - 128. 8 years from now: G + 8 = 3(M + 8) → G = 3M + 16. Equating: 9M - 128 = 3M + 16 → 6M = 144 → M = 24. Then G = 3(24) + 16 = 88. 8 years ago: M = 16, G = 80. Ratio = 16:80 = 1:5.

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