or
or
Let's first calculate the work done by the 3 pumps in 2 days, which is equivalent to emptying the tank:
3 pumps * 8 hours/day * 2 days = 48 pump-hours of work
Now, we want to find out how many hours a day 4 pumps must work to empty the tank in 1 day. Let "x" be the number of hours a day they need to work.
4 pumps * x hours/day * 1 day = 4x pump-hours of work
Since the amount of work done is the same (emptying the tank), we can set up the equation:
48 pump-hours of work = 4x pump-hours of work
Now, solve for "x":
4x = 48
Divide both sides by 4:
x = 48 / 4
x = 12
So, 4 pumps must work 12 hours a day to empty the tank in 1 day.
