Question

At noon, your family starts out .from Louisville to go to Memphis driving at 40 mi/h. Your uncle leaves Memphis to come to Louisville two hours later. He is taking the same route and driving at 60 mi/h. The two cities are 380 miles apart. At what time do the cars meet?

Answer 1

If you add the two distances driven you need to get 380.

You also need to see that the time driven by each driver is the same.

So, if your family drives distance d, yur uncle drives 380-d, in the same time:

d/40 = (380-d)/60
d/40 = 380/60 - d/60
3d/120 = 760/120 - 2d/120
5d = 760
d = 152

152/40 = 3.8 hr
228/60 = 3.8 hr

So, the cars meet at 3:48 pm