Pipe A fills in 4 h, B fills in 8 h. Both open, fill time?
Q1. Pipe A fills in 4 h, B fills in 8 h. Both open, fill time?
Answer: 2 h
Explanation: Combined rate 1/4 plus 1/8 equals 3/8 so about 2.67 hours. Work each step carefully; ISSB math rewards accuracy under time pressure.