Answer:
Valterri's unit rate for Day 1 in minutes per lap is 3.5 or 3 minutes and 30 seconds.
Explanation:
Let's find Valterri's unit rate for Day 1 in minutes per lap, this way:
Total time = 1 hour, 13 minutes, and 30 seconds
Total time = 60 minutes + 13 minutes + 30 seconds
Total time = 73 minutes and 30 seconds
Total time = 73.5 minutes (30 seconds = 0.5 minutes)
Number of laps = 21
Valterri's unit rate for Day 1 in minutes per lap = Total time/Number of laps
Valterri's unit rate for Day 1 in minutes per lap = 73.5/21
Valterri's unit rate for Day 1 in minutes per lap = 3.5