If you can clean the house in 3 hours and your sloppy friend can completely mess it up
Chapter 6, Problem 74(choose chapter or problem)
If you can clean the house in 3 hours and your sloppy friend can completely mess it up in 6 hours, then x 3 - x 6 = 1 can be used to find how long it takes to clean the house if you both work together.
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