math70
posted by Helo on .
An executive drove from home at an average speed of 30 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 75 mph. The entire distance was 156 mi. The entire trip took 3 h. Find the distance from the airport to the corporate offices.

first distance  x miles
distance by helicopter  156x
x/30 + (156x)/75 = 3
times 150
5x + 2(156x) = 450
5x + 312  2x = 450
3x = 138
x = 46
distance from airport to office = 15646 = 110
check:
46/30 + 110/75 = 3