- A14 h
- B15 h
- C5 h
- D16 h
Step-by-Step Solution
One 3-hour cycle: . After 4 cycles (12 h): ; A: ; B: ; C's hour adds exactly . Total 15 h. (5 h is all three running together.)
Answer: B) 15 h
Pipes A, B and C fill a tank in 12, 15 and 20 hours. They are opened in turn for one hour each in the order A, B, C, A, B, C, … How long will the empty tank take to fill?
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