<PRE><B>Question 322579</B>
Airplane  Time = 1000/x  where x is the speed of the plane
Airplane B Time = 1000/x+50 ( 50 mph faster)
..
Time taken by airplane A - Time by Airplane B =1
1000/x - 1000/ x+50=1 
LCM = x(x+50)
1000(x+50)- 1000x= x(x+50)
1000x+50,000 - 1000x=x^2 +50x
x^2+50x-50000=0
x^2+250x-200x-50000=0
x(x+250)-200(x+2 b50)=0
(x+250)(x-200)=0
x= 200 mph speed of plane A
speed of plane B = 250 mph
distance traveled = 1000miles
time it traveled = 1000/250 = 4 hours</PRE>