Problem Solving (PS) | If it takes Jacob x hours to complete a project and it takes Mike y

Jacob's 1 hour's work = 1/x
Mike's 1 hour's work=1/y

Jacob and Mike's 1 hour's work=1/x + 1/y
= (x+y)/xy

Now (x+y)/xy is done in 1 hour
So, the entire work will be done by = xy/(x+y), which is option A.
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