Let the speed of faster plane be x miles/hour
so,
the speed of the other plane will be (x-20) Mph
The distance covered by both of them in 2hours:
Faster plane= 2 h × (x )Mph = 2x miles
Slower plane = 2(x-20) miles
Now according to question,
2x + 2(x-20) = 1600
2x + 2x -40 = 1600
4x = 1560
x = 440miles
Therefore the speed of faster plane = 400Mph
and the slower one will be (400-20)Mph = 380Mph
