18 mph. OK. Let's call the speed of the slower cyclist X, And since the faster cyclist is 3 times faster, that speed will be 3X. So their combine closing speed will be (X + 3X) and over a period of 4 hours, they travel 96 miles. So the equation becomes: 4(X + 3X) = 96 Now solve for X 4(X + 3X) = 96 4(4X) = 96 16X = 96 X = 6 So the slower cyclist has a speed of 6 mph. And since the faster cyclist is 3 times faster, that speed is 3*6 = 18 mph.