Question:
An oil tanker can be emptied by the main pump in 5 hours. An
Last updated: 7/9/2022
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An oil tanker can be emptied by the main pump in 5 hours. An auxiliary pump can empty the tanker in 7 hours. If the main pump is started at 5 PM, when should the auxiliary pump be started so that the tanker is emptied by 9 PM?