A 150-pound person uses 6.6 calories per minute when walking at a speed of 4 mph. how long must a person walk at this speed to use at least 240 calories?

At 4 mph 6.6 calories are used in = 1 minute

So, at 4 mph, 240 calories are used in=

= 36.36 minutes

Hence, a person must walk for 36.36 minutes to burn 240 calories.

To find the distance a person should walk, when the speed is 4 miles per hour.

In 60 minutes a person is walking = 4 miles

So, in 36.36 minutes a person will walk =

= 2.424 miles

Hence, by walking 2.424 miles in 36.36 minutes a person can burn 240 calories,