Question 59200
Let the speed of the slower plane be x. The faster planes speed must be x+150.
Their combined speed is 2x + 150 miles per hour.
In two hours they travel 2(2x +150) miles
so 2(2x + 150)= 1900
2(2x + 150)= 1900
4x + 300 = 1900
4x = 1600
x=400
so the faster plane is travelling at 400+150=550 miles per hour.