Let
x-----> the time in minutes
y------> the number of gallons of water
we know that
the unit rates is equal to
[tex]\frac{y}{x} = \frac{42}{10}=4.2\frac{gal}{min}[/tex]
the unit rate is equal to the slope of the linear equation
then
[tex]y=4.2x[/tex]
Problem
1) How many gallons of water will Elyse use in three minutes in the shower?
For x=3 minutes
substitute in the equation above
[tex]y=4.2x[/tex]
[tex]y=4.2*3[/tex]
[tex]y=12.6 gal[/tex]
the answer is
12.6 gal
