The Conventional Approach

Assume that if one man would take m days to complete the work alone. He does 1/m part of the work in a day. Similarly, if a woman takes w days to complete the work alone, she does 1/w part of the work in a day. If there are M men and W women who together take 15 days, we know that 15*(M/m + W/w) = 12*[(M + 1)/m + (W – 1)/w]. We have to find out how long (M + 2) men and (W – 2) women will take to complete the work.

How do we proceed after this? We’re stuck.

Giving up? But, there is a solution. Perhaps, a hint would do.

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