Question

Lisa started to drive from Boston to Washington, DC, which is 440 miles away, at 8:00 AM. For the first four hours of her trip, Lisa 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 4:00 PM?

Answer 1

60 mph

Step-by-step explanation:

The total distance is provided to be 440 miles

For first four hours, we are given the speed and time. So, we can calculate the distance. As,

Speed = distance/ time

Distance = speed * time = 50 * 4 = 200 miles

Now, we need to calculate the speed.  

Since, we know that the remaining distance is = 440 -200 = 240 miles

Remaining time = 8-4 = 4 hours

Thus, the speed for remaining journey = distance / time = 240 / 4 = 60 mph