Question

8.) If 5 men, 7 women or 9 boys can dig a ditch in 15 days, then in
how many days can 1 man, 1 woman and 1 boy dig it ?
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Answer 1

5 men = 15 days => 1 man = 15*5 = 75 days
7 women = 15 days => 1 woman = 7*15 = 105 days
9 boys = 15 days => 1 boy = 9*15 = 135 days