A couple of weeks ago I decided to make the 1200 mile drive from Ivins to Austin. I was so excited to get there that I drove 30 miles per hour faster going to Austin, than I did returning to Ivins. My total drive time, both there and back, was 25 hours. How fast was I driving in my return trip to Ivins? Round to the nearest mph.

Solution:

The speed of driving in my return trip to Ivins is x mph

1200/x + 1200/(x+30) = 25

So

x=83.3

So the speed of driving in my return trip to Ivins is 83.3 mph