Multiple choice

A piece of work can be done by 6 men and 5 boys in 6 days or 3 men and 4 boys in 10 days. In how many days can it be done by 9 men and 6 boys?

  1. 2

  2. 3

  3. 1

  4. 4

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

Let 1 man's work = m, 1 boy's work = b per day. 6m + 5b = 1/6, 3m + 4b = 1/10. Solving: 18m + 15b = 1, 18m + 24b = 1.8. Subtracting: 9b = 0.8, b = 0.8/9, m = (1/6 - 5b)/6 = 1/36 - 5b/6. 9m + 6b = 1/3 = 3 days.

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