Atank currently holds 5 gallons of water. it is being filled at the rate of 1/4 gallon per minute. how long will it take for the tank to hold 9 gallons of water?

So we know the tank already has 5 gallons and we need 9. This means we need 4 more gallons in order to fill up the tank.

If 1/4 gallon is being filled per minute we need to find out how many 1/4 gallons makes up 4 gallons in total.

4 of the 1/4 gallons makes up 1 whole gallon. So since we need 4 whole gallons we would need 16 of the 1/4 gallons.

This means that it will take 16 minutes for the tank to hold 9 gallons of water.