A 150-lb person who runs at 6 mph for 1 hr burns about 720 calories. The same person, walking at 2 mph for 90 min, burns about 240 calories. Suppose a 150-lb person runs at 6 mph for 75 min. How far would the person have to walk at 2 mph in order to burn the same number of calories as burned when running? miles. The person has to walk (Type an integer or a decimal.)