A bathtub can hold up to 70 gallons of water. The bath tub drains at a constant rate. when you first see the bath tub, it has 42 gallons of water in it. Three minutes later it has 14 gallons left in it. Use a signed number, and include the unit of measurement in your answer.
a. at what rate is the amount of water changing each minute?
b. How many more minutes will it take for the tub to drain completely?
c. How many minutes before you arrived was the tub completely full?