Answer:
1. 48 seconds or 0.8 minutes per lap.
2. 1,008 seconds or 16.8 minutes to run 21 laps.
Step-by-step explanation:
1. Turn 4 minutes into seconds which is 240 then divide it by 5 and you'll get 48 seconds per lap. 48/60 to turn it into minutes = 0.8 minutes
2. use 48 seconds and times it by 21 which gets you 1,008 seconds, then divide that by 60 which gets you 16.8 minutes to run 21 laps.
