SOLUTION: If bob can paint a house in 5 hours and joe can paint a house in 3 hours how many hours will it take to paint a house together?

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Question 799150: If bob can paint a house in 5 hours and joe can paint a house in 3 hours how many hours will it take to paint a house together?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of painting
Bob's rate: ( 1 house ) / ( 5 hrs )
Joe's rate: ( 1 house ) / 3 hrs )
Let +t+ = the time in hours for
them to paint the house together
----------------------------
+1%2F5+%2B+1%2F3+=+1%2Ft+
Multiply both sides by +15t+
+3t+%2B+5t+=+15+
+8t+=+15+
+t+=+1.875+
+.875%2A60+ minutes
It will take them 1 hr and --- minutes
( you can do the above calculation )