Question

the amount of water in a bathtube as it drains can be modeled by this equation with y representing the number of gallons of water in the tub and x representing the time, in minutes, that the tube has been draining y=-7.3x+39.7 after how many minutes will the tub have 17.8 gallons of water remaining

Answer 1

Since
`y` is representing the number of gallons of water in the tub, we need to replace
`y` with the number of gallons remaining in the tube to find the time. Fortunately, the problem is telling us just that: 17.8 gallons. The only thing left is replacing that value in the equation, and solve for
`x` to find the time:

`17.8=-7.3x+39.7`

`7.3x=21.9`

`x= (21.9)/(7.3)`

`x=3`

We can conclude that after 3 minutes the tub will have 17.8 gallons of water remaining.