Final answer:
To find out how long Tomas took to run back from the fence, subtract the time it took him to run to the fence (21 seconds) from the total round trip time (58 seconds), resulting in 37 seconds.
Step-by-step explanation:
The student is asking how long it took Tomas to run back from the fence if the total time for the round trip was 58 seconds and the time to reach the fence was 21 seconds. To find the time taken to run back, we subtract the time taken to reach the fence from the total time.
Step 1: Total time for the round trip = 58 seconds
Step 2: Time taken to reach the fence = 21 seconds
Step 3: Time taken to run back from the fence = Total time - Time to reach the fence
Step 4: Time taken to run back from the fence = 58 seconds - 21 seconds = 37 seconds
Tomas took 37 seconds to run back from the fence.