<PRE><B>Question 414253</B>
sally 15 minutes
Lisa 25 minutes
..
Sally does 1/5 of job in 1 minute
Lisa does 1/25 of the job in 1 minute
..
Together they do 1/15 +1/25 of the job in 1 minute
LCD = 75
(5+3)75 of the job in 1 minute
8/75 of the job in 1 minute
so together they take 75 /8 minutes
9 3/8 minutes
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