Question

Michel started to drive from New York to Washington, DC, which is 120 miles away, at 7:00 AM. For the first hour and a half of her trip, Michel was driving at a speed of 50 mph. What was her average speed during the second part of the trip, if she reached Washington at 10:00 AM?

Answer 1

30 mph

Explanation:

Answer 2

30 mph

Explanation:

First we need to find the distance travelled in the first 1h30m.

We can do that multiplying the speed by the time travelled, so we have:

Distance1 = 50 * 1.5 = 75 miles

If the total distance is 120 miles, Michael still needs to travel 120 - 75 = 45 miles.

And if the total time travelled is 3 hours (10 AM - 7 AM), the second part of the travel has a duration of 3h - 1.5h = 1.5h

So if the distance is 45 miles and the time is 1.5 hours, we can find the speed of the second part:

45 = speed * 1.5

speed = 45/1.5 = 30 mph