Physics
posted by Jayd .
You drive your car from home at an average spped of 78km/h for 2 h. Halfway to your destination, you develop some engine problems, and for 4 h you nurse the car the rest of the way. What is your average velocity for the entire trip?

You spent six hours to take a trip of distance twice 78km/hr*2hrs
velocity= 2*78*2/6 km
check my thinking. 
This is the answer that I got when I worked it, but the webassign homework that I have marked the answer incorrect. I thought that maybe I was doing something wrong or missing an important part of the problem, thus causing my answer to be wrong.

The answer would be 52 km/h.

That is the answer above. 2*2*78/6=52 km/hr