Answer: see below for work done
To get the car's average speed, all you really need to know is
the total distance travelled by the car
the total time it needed to cover that distance
In your case, you know that the car travelled for a total of 80 miles and that it needed 100 minutes to do so.
Since you need to express the average speed in miles per hour, not miles per minute, you're going to have to use a simple conversion factor to get you from minutes to hours.
First, calculate the average speed in miles per minute
[tex]v_{avg=\frac{d_{total}}{t_{total}}[/tex]
[tex]v_{avg=\frac{80 miles}{100 minutes}[/tex] = 0.8 mi/min
Convert to miles per hour
[tex]\frac{0.8 miles}{1 minute}[/tex] x [tex]\frac{60 minutes }{1 hour}[/tex]= 48mph
if you need this in metres per second you would take 48mph divide it by 2.237 =21.46m/s
if you need this in kilometres per hour you would take 48mph multiply by 1.609 =77.25km/h
