An executive drove from home at an average speed of 40 mph to an airport where a helicopter was waiting. The executive boarded the helicopter and flew to the corporate offices at an average speed of 80 mph. The entire distance was 280 mi. The entire trip took 4 h. Find the distance from the airport to the corporate offices.
If he drove for x hours, then
40x + 80(4-x) = 280
x = 1
so he drove 40 mi and flew 240 mi