In this question, you are given the plane 1 speed(496miles/h), plane1 depart time(8:00), plane 2 speed(558miles/h) and plane2 depart time(8:30 or 8.5 hour). Both of the planes left from the same airport so their traveling distance should be same. They also arrive in same time. Then the equation would be:
duration = arriving time - depart time
duration1= x= arriving time - 8h
duration2= y= arriving time -8.5h= (arriving time - 8h) -0.5h= x-0.5h
speed1 * duration1 = speed2 * duration2
496 * x = 558* (x-0.5)
496x = 558x - 279
279= 558x- 496x
279= 62x
x= 4.5hour
