MAth Question ALgebra

Question

A 800-mile, 7-hour plane trip was flown at two speeds. For the first part of the trip, the average speed was 107 mph. For the remainder of the trip, the average speed was 124 mph. How long (in hours) did the plane fly at each speed?

Answer 1

Let t = the time flown at 107 mph and 7-t be the remaining time flown at 124 mph.

107t + 124(7-t) = 800

-17t +868 = 800

t = 68/17 = 4 hours

7-4 = 3 hours

The plane flew 4 hours at 107 mph and 3 hours at 124 mph.