The tub is said to drain 24 gallons of water in 5 minutes.
The rate at which water is drained is;

The volume is given as 24 gallons.
Recall that 1 US gallon is equivalent to 16 US cups.

Time taken is given as 5 minutes.
since the rate is in cups per second, we need the convert the time to seconds;

Using the rate formula, The rate in cups per second is;

The rate in cups per second is 1.28 cups per second