- A12 min
- B18 min
- C24 min
- D15 min
Step-by-Step Solution
Normal rate . First 6 min at half: . Then min. Total 15 min. (24 min keeps the half rate throughout.)
Answer: D) 15 min
Pipes A and B fill a tank in 20 and 30 minutes. They are opened together, but a partial blockage halves the flow of both for the first 6 minutes; then it clears. How long does the tank take to fill?
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