pedro walks at a rate of 4 miles per hour and runs at a rate of 8 miles per hour. Each Week, his exercise program requires him to cover a total fist of 20 miles with some combination of walking and/or running.

A. write an equation that represents the different amounts of time pedro can walk, x, and run, y, each week.
B. graph the equation
C. what is the y- intercept? what does this tell you?