Answer
Question 1
Option C is correct.
Runner A and B are tied.
Question 2
Option B is correct.
Runner B is the faster runner in this time period.
Question 3
Option A is correct.
Runner A is the faster runner in this time period.
Step-by-step explanation
Average speed is distance covered divided by time taken.
Question 1
For the first 9 seconds
Runner A
Distance covered = 120 - 0 = 120 m
Time Taken = 9 - 0 = 9 seconds
Average speed = (120/9) = 13.33 m/s
Runner B
Distance covered = 120 - 0 = 120 m
Time Taken = 9 - 0 = 9 seconds
Average speed = (120/9) = 13.33 m/s
Both runners are tied.
Question 2
For 9 seconds to 20 seconds
Runner A
Distance covered = 168 - 120 = 48 m
Time Taken = 20 - 9 = 11 seconds
Average speed = (48/11) = 4.36 m/s
Runner B
Distance covered = 213 - 120 = 93 m
Time Taken = 20 - 9 = 11 seconds
Average speed = (93/11) = 8.45 m/s
Runner B is the faster runner in this time period.
Question 3
For 20 to 31 seconds
Runner A
Distance covered = 287 - 168 = 119 m
Time Taken = 31 - 20 = 11 seconds
Average speed = (119/11) = 10.82 m/s
Runner B
Distance covered = 287 - 213 = 74 m
Time Taken = 31 - 20 = 11 seconds
Average speed = (74/11) = 6.73 m/s
Runner A is the faster runner in this time period.
Question 4
For 0 to 31 seconds
Runner A
Distance covered = 287 - 0 = 287 m
Time Taken = 31 - 0 = 31 seconds
Average speed = (287/31) = 9.26 m/s
Runner B
Distance covered = 287 - 0 = 287 m
Time Taken = 31 - 0 = 31 seconds
Average speed = (287/31) = 9.26 m/s
Both runners are tied in this time interval.
Hope this Helps!!!