Answer:
3.43 seconds to do push ups and 2.66 seconds for him to do sit ups in the given time of 48 seconds ( to find the difference of time of each exercise done in the two different time, subtract each time unit from each other)
Explanation:
for him to do 7 push ups and 15 sit ups in 66 seconds it would take time 4.71 second (5 seconds rounded) to do push ups. it would take him 2.20 seconds (2 seconds rounded) for him to do 15 sit ups in 66 seconds. for him to do it in 48 seconds, it would take him 3.43 (3 seconds rounded) to do 7 push ups in 48 seconds. for him to do 9 sit ups in 48 seconds it would take in 2.66 seconds ( 3 seconds rounded) for him to complete them in the given time.