Mariam left Riverside, California, driving her motorhome north on Interstate 15 towards Salt Lake City at a speed of 40 miles per hour. Half an hour later, Porter left Riverside in his car on the same route as Mariam, driving 50 miles per hour. Solve the system: [40y = 50z ly=z+ A. for z to find out how long it will take Porter to catch up to Mariam. B. What is the value of y, the number of hours Mariam will have driven before Porter catches up to her?
