SOLUTION: Brett can paint a room in exactly 6 hours. If Dave helps him, they can paint it in exactly 4 hours. How long would it take Dave to paint the room alone

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Question 619037: Brett can paint a room in exactly 6 hours. If Dave helps him, they can paint it in exactly 4 hours. How long would it take Dave to paint the room alone
Found 2 solutions by scott8148, richwmiller:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
in the 4 hrs that they work together, Brett paints 2/3 of the room (4 hr / 6 hr)

so it takes Dave 4 hr to paint 1/3 of the room

how long to paint 3/3 (the whole room)?

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
4/6+4/x=1
2/3*4/x=1
4/x=1/3
x=12
12 hours for Dave alone.