4991. 3 pumps, working 8 hours a day, can empty a tank in 2 days, How many hours a day must 4 pumps work to empty the tank in 1 day?
- A. 13
- B. None of these
- C. 14
- D. 12
Check answer and explanation
Answer: 12
Explanation Let's calculate the total pump-hours required to empty the tank: 3 pumps * 8 hours/day * 2 days = 48 pump-hours If 4 pumps need to empty the tank in 1 day: Let x be the number of hours they need to work: 4 pumps * x hours/day * 1 day = 48 pump-hours 4x = 48 x = 12