Two planes leave an airport at the same time, one flying east, the other flying west. The eastbound plane travels 20 mph slower. They are 1600 mi apart after 2 hr. Find the speed of each plane.

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