Answer:
30 seconds
Step-by-step explanation:
Speed of person :
72 feets in 9 seconds
Distance = 72 feets ; time = 9 seconds
Speed = distance / time
Speed = 72 / 9 = 8 ft/s
Length of sidewalk = 240 feets
Time it takes to move from one end to the other :
Time = distance / speed
Time = 240 feets / 8 feets /sec
Time taken = 30 seconds
