Answer:
3/3 is equivilant to 1.
Multiplying 6/4 by 1, would be 6/4. Also, multiplying 6/4 by 3/3 would be 18/12, which could be simplified to 6/4.
Hope this helps!
.25(4) = 1 gallon
.25(8) = 2 gallons
.25(12) = 3 gallons
.25(16) = 4 gallons
.25(20) = 5 gallons
it would take 20 minutes to remove half the water (aka 5 gallons)
The answer to this problem is letter d