Question

Two planes start from los angeles international airport and fly in opposite directions. the second plane starts 1 2 hour after the first plane, but its speed is 40 kilometers per hour faster. two hours after the first plane departs, the planes are 2860 kilometers apart. find the airspeed of each plane.

Answer 1

Let x be the speed of the slower plane, in km/h. Then the faster plane travels at x+40.
[2 hrs at speed x] + [(2 hrs - 1/2 hour) at speed (x+40)] = 2860(2x) + (1.5)(x+40) = 2860 solve for xx=800x+40=840
Plane 1 800 km/h
Plane 2 840 km/h