Question 484744
Plane A speed = x mph
Plane B speed = x+70

They are travelling towards each other 
combined speed = x+x+70= 2x+70
Time = 3 hours

distance = 2160

time = d/r
3=2160/(2x+70)
3(2x+70)=2160
6x+210=2160
6x=1950
x= 1950/6
x= 325 mph speed of one plane 
speed of other plane = 325+70 = 395 mph

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