Answer:
C. 1
Explanation:
Distance between workplace and home = 45 miles
Time taken to drive from his workplace to home = 30 minutes
The time taken for him to go back home to retrieving his wallet and come back to the workplace is twice as long.
This means if the time for him to go from his workplace to home is 30 minutes,then the time take for him to go from his home to the workplace is 30×2=60 minutes.
The distance is: 2×45 = 90 miles
Time taken : 30 + 60 = 90 minutes
Average speed = Distance / Time
= 90/90
= 1 minute/mile.
So the average speed is 1 minute/mile