A 155 pound person burns about 500 calories per hour playing racquetball. one pound id equal to 3500.

Q - If the person were to rest 5 minutes for every 30 minutes of playing, how long would it take to burn 1 pound?

Lets t time and c the calories burned p pound burns

p = c/t

155lb=500cal/1h

1lb = 3500 cal

30-5 = 25 min of workout 25/60 = 5/12 hr

1/t=c/5/12

1 lb = 3500 cal

500/1=c/5/12

c=208 cal

3500/t=208 / (5/12)

3500/t=500

t = 7 min to burn 1 pound calorie