# A car travels 40 miles in the first hour and 50 miles in the second hour. What is the car's average speed over the entire trip?

Jan 27, 2016

45 miles per hour

#### Explanation:

Average velocity is equal to the total distance traveled divided by the time it took to travel that distance.
$v = \frac{d}{t}$

In this case we are told two distances. So the total distance traveled is:
$d = {d}_{1} + {d}_{2}$
$d = 40 + 50 = 90 \text{ miles}$

We are also told about two time intervals. Each is an hour in length.
$t = {t}_{1} + {t}_{2}$
$t = 1 + 1 = 2 \text{ hours}$

Now we can calculate the average velocity for the entire trip using the first equation.
v = (90 " miles")/(2 " hours") = 45 "miles"/"hour"