A 450 gallon tank full of water is draining at a rate of 20 gallons per minute. We can represent the situation with the equation:
y
=
450
−
20
x
y
=
450
-
20
x
where x is the number of minutes that have passed by, and y is the amount of water in the tank. How long will it take for the tank to have 200 gallons?
