Question

If two pipes A and B function simultaneously, an empty tank will be filled in 20 hours. If pipe A, working alone, fills this empty tank 9 hours faster than pipe B can fill working alone, then how many hours does it take pipe B to fill this empty tank while working alone?

• A. 45 hours
• B. 39 hours
• C. 42 hours
• D. 36 hours

Answer 1

Answer: (A)