SOLUTION: Jill can build a doll house in 58 minutes, working by herself, and Jimmy can do it in 69 minutes working by himself. How long will it take them to build one doll house working toge

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Question 259953: Jill can build a doll house in 58 minutes, working by herself, and Jimmy can do it in 69 minutes working by himself. How long will it take them to build one doll house working together?
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Jill can build a doll house in 58 minutes, working by herself, and Jimmy can do it in 69 minutes working by himself. How long will it take them to build one doll house working together?
.
Let t = time it takes for both working together
then
t(1/58 + 1/69) = 1
Multiplying both sides by (58)(69)
t(1/58 + 1/69) = 1
t(69 + 58) = (58)(69)
t(127) = 4002
t = 4002/127
t = 31.51 minutes