Car travels for 15mins at 48mph it then travels for 2 hours at 60mph it then travels for45mins at 40mph what is the car average speed for the whole journey?

55.5mph

Explanation

First lets find the total time driven.

15+180+45 = 240

Now knowing they drove for 240 minutes we can use percentages to see the percent driven at a certain speed in this time.

There are many ways to do this but heres how I did it.

I then multipled the speed by the number of minutes to find the average.

48*15 = 720

60*180 = 10800

40*45 = 1800

These represent total miles driven in that time but we dont need that, to find the average we then need to add them all together.

720+10800+1800 = 13320

Now we can divide this number by 240 to find the real average, because 240 is the whole time driven.

Our answer is 55.5

So we now know the average speed driven is 55.5