Multiple choice general knowledge math & puzzles

Man Wrinkle spent one-fourth of his life as a boy, one-eighth as a youth, and one-half as an active man. If Man Wrinkle spent 10 years as an old man, then how many years did he spend as an active man?

  1. 20

  2. 60

  3. 40

  4. 80
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C Correct answer
Explanation

Let x be Man Wrinkle's total lifespan. Boy = x/4, Youth = x/8, Active man = x/2, Old man = 10 years. So x/4 + x/8 + x/2 + 10 = x. Combining fractions: 7x/8 + 10 = x, giving x/8 = 10, so x = 80 years total. Active man period = 80/2 = 40 years.

AI explanation

Man Wrinkle spent 1/4 of his life as a boy, 1/8 as a youth, and 1/2 as an active man, which together account for 1/4+1/8+1/2 = 7/8 of his life. The remaining 1/8 of his life was spent as an old man, and since that equals 10 years, his total life span is 80 years. His time as an active man is then 1/2 of 80 = 40 years.

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