A​ 150-pound person burns 5.8 calories per minute when walking at a speed of 4 miles per hour. While​ walking, this person eats a snack that has 50 calories. This snack subtracts from the calories burned while walking. How long must the person walk at this speed to burn at least 200 calories​? Use pencil and paper. Describe what values the person could change so that the amount of time spent walking would be less.