Question 359494
Chris's average speed for a 6 hour trip was 70 mph.  For the first 4 hrs, Chris drove at 62 mph.  What was his average speed for his last 2 hours of his trip?

The total distance traveled was {{{70 * 6 = 420}}}miles.  During the 1st four hours, The distance traveled was {{{62*4 = 248}}}.  Therefore 172 miles was traveled the last 2 hours, and the average speed would be {{{172/2 = 86}}} miles per hour.