Question

Two planes which are 2265 miles a apart, fly toward each other. Their speed differs by 55 mph. If they pass each other in 3 hours, what is the speed of each?

Answer 1

use relative velocity

Answer 2

let their speeds be v1 and v2
Relative speed(or frame of reference);
Assume one plane to be at rest, then the speed of other will become (v1+v2)

v2-v1=55.......(1) Given
so, v2=v1+55
so, (v1+v2)= v2+v2+55 = 2.v2+55
Now,
distance/speed = time
2265/(2v2+55) = 3
hence v2 and v1

Answer 3

v2=350 mph
v1=295 mph