Answers:
1.2 minutes
0.833 laps
25.2 minutes
Step-by-step explanation:
To know the number of minutes per lap, we need to divide the number of minutes by the number of laps that Lin runs. So:

In the same way, to know the number of laps per minute, we need to divide the number of laps by the number of minutes that Lin runs. So:

Finally, if Lin runs 21 laps at the same rate and we know that Lin takes 1.2 minutes per lap, we can calculate the time as:
21 laps x 1.2 minutes per lap = 25.2 minutes