Conveyor Belt

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Conveyor Belt

by gmatwriter » Tue Mar 23, 2010 6:18 pm
Please Explain:

If both conveyor belt A and conveyor belt B are used, they can fill a hopper with coal in one hour. How long will it take for conveyor belt A to fill the hopper without conveyor belt B?

1. Conveyor belt A moves twice as much coal as conveyor belt B.
2. Conveyor belt B would take 3 hours to fill the hopper without belt A.

D
Source: — Data Sufficiency |

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by papgust » Tue Mar 23, 2010 7:07 pm
Conveyor A and B can fill in 1 hour. You want to know individual rate of A.

1. A fills twice as fast as B.

Assume A takes 'x' hours, B takes '2x' hours.
1/x + 1/2x = 1
You can find 'x' by solving. Sufficient.

2. B takes 3 hours without A.

Assume A takes 'x' hours.
1/x + 1/3 = 1
You could find 'x' by solving. Sufficient.