SOLUTION: A man can dig a ditch in 3 hours and his daughter can dig the same size ditch in 5 hours. Working together, how long will it take them to dig the ditch?

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Question 734810: A man can dig a ditch in 3 hours and his daughter can dig the same size ditch in 5 hours. Working together, how long will it take them to dig the ditch?
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
1/3+1/5=1/X
(5+3)/3*5=1/X
8/15=1/X CROSS MULTIPLY.
8X=15
X=15/8
X=1.875 HOURS WORKING TOGETHER.