For a linear function you can use the formula y=mx+b
m is the slope (also known as the rate of change)
b is the y intercept (the value y is at when x is 0). For this problem the bucket starts out empty so there is no y-intercept that needs to be written in the equation.
To find slope divide the inches of water by the total number of minutes given. 12/36=1/3
Plug your slope and y-intercept into the equation.
