You would first have to convert 5 gallons into ounces. There are 128 ounces in 1 gallon. So 128×5= 640. Now you have 640 ounces. Since Rick is trying to see how many hours it will take to be half full, you divide. So 640÷2=320. Now you have 320 ounces. Now we can find out how many hours it will take by dividing by 5. So 320÷5=64. It will take 64 hours to get Rick's bucket to be half full.