<span>Turn 1 3/4 into a decimal number: 1.75 So, 120 miles in 1.75 hours, but we want to know miles in *one* hour. Divide both numbers by 1.75. 120/1.75 miles in 1.75/1.75 hour = 120/1.75 miles in 1 hour. 120/1.75 is 68.57 miles in one hour, so 68.57 mph.</span>
