Multiple choice

If 4 men and 6 boys can do a work in 8 days and 6 men and 4 boys can do the same work in 7 days, then how many days will 5 men and 4 boys take to do the same work?

  1. 5

  2. 8

  3. 6

  4. 7
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let one man's work per day be m and one boy's work per day be b. From given: 4m + 6b = 1/8 and 6m + 4b = 1/7. Solving these equations gives m = 1/56 and b = 1/112. For 5 men and 4 boys: daily work = 5/56 + 4/112 = 5/56 + 2/56 = 7/56 = 1/8. Therefore, they complete the work in 8 days.

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