1.5 minutes or 90 seconds. which is 1/40 of an hour. mph means exactly what it stands for "miles per hour" so you take 1/40 which gets you to 90 seconds.
At 20 mph how long would it take to drive one mile?
About 51 seconds.
2 minutes.
About 65 seconds.
55.38 seconds.
1 minute
5.5 minutes
16.51 seconds.
about 3 minutes
About 1 minute 12 seconds.
6.42 hours
About 1 minute 42 seconds.