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MBMT Guts Rounds
2015.9
2015.9
Part of
MBMT Guts Rounds
Problems
(1)
MBMT Guts #9
Source:
3/29/2015
Alice and Bob are builders; Charlie is a destroyer. Alice can build a car in
20
20
20
hours and Bob can build a car in
10
10
10
hours, while Charlie destroys a car in
40
40
40
hours. If Alice and Bob are working together on a car Charlie is destroying, how many hours will it take for Alice and Bob to finish building the car?