Let r be the rate of the slower cyclist, in miles per hour (mph) Then the rate of the faster cyclist is 2x mph. For the total distance, you have then this equation 3x + 3*(2x) = 90 miles, or 3x + 6x = 90 9x = 90 x = 90/9 = 10. ANSWER. The rate of the slower cyclist is 10 mph; that of the faster cyclist is 2*10 = 20 mph.