Mary averages 12 mph riding her bike to school. Averaging 36 mph by car takes her one-half hour less time. What is the distance to Mary's school?
+36915 The distance is the same
rate * time = distance (using x as the time on the bike)
12 * x = 36 * (x-1/2)
18 = 24x
x = 3/4 hr On the bike for 3/4 hr = 3/4 hr * 12 m/hr = 9 miles (one way)
