The table below shows the number of calories used per minute as a function of an individual's body weight for three sports:
Activity100 lb120 lb150 lb170 lb200 lb220 lb

a) Determine the number of calories that a 200 lb person uses in one half-hour of walking . calories

b) Who uses more calories, a 170 lb person swimming for one hour, or a 220 lb person bicycling for a half-hour?

c) Does the number of calories of a person walking increase or decrease as weight increases?