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Word Problems, Work and Rate Problems

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by swerve » Tue Jul 14, 2026 7:16 am

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Water is pumped in and out of a tank using an inlet and outlet pipe, respectively. If the tank is initially empty, how much time will it take to fill the tank when both pipes are opened simultaneously?

1. The inlet pipe takes \(20\) minutes to fill the empty tank, and the outlet pipe takes \(60\) minutes to empty a full tank

2. The amount of water the tank can hold is \(100\) gallons

The OA is A
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Source: — Data Sufficiency |

Statement 1 alone is sufficient because the combined rate is simply (1/\text{inlet time} - 1/\text{outlet time}). Statement 2 is irrelevant unless the problem is asking for the answer in gallons per minute rather than total time.
Edit by fnf 1 day ago
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