- A5
- B10
- C6
- D7.5
Step-by-Step Solution
A runs the full 15 min filling 15/20 = 3/4. B must fill the remaining 1/4, and at 1/30 per minute that needs minutes.
Answer: D) 7.5
Two pipes A and B can fill a tank in 20 minutes and 30 minutes respectively. Both are opened together, but B is closed after some time so that the tank is exactly full in 15 minutes. After how many minutes should B be closed?
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