Q. Pipe A can fill a tank in 9 hours and pipe B in 18 hours. If pipe A works for 3 hours and then pipe B alone finishes the work, how long will the total work take?
✅ Correct Answer: (A)
6 hours
Explanation: A does 1/3 work. Remaining 2/3 done by B in 12 hours → total 15 hours.
Explanation by: Hriday
A does 1/3 work. Remaining 2/3 done by B in 12 hours → total 15 hours.