Answer:
10 hours
Step-by-step explanation:
volume of lower portion = 85x125x40 = 425,000
volume of upper portion = 20x30x125 = 75,000
in 1.5 hours, the pump removed 75,000
in one hour it removed 50,000 (75000/1.5 = 50,000)
425,000 / 50,000 = 8.5 hours for bottom portion
8.5 + 1.5 = 10 hours total time for top and bottom
