Question 834454
Let F = fastest, and S = slowest.
They're covering the same distance.
F is 1.2 times as fast as S (3.6/3 -- the .6 is 36/60 [minutes])
If F = S + 75 and F = 1.2S, we can substitute the value of F
1.2S = S + 75
Subtract S from each side
.2S = 75
Multiply each side by 5 (to get a whole S)
S = 375; therefore F = 450 (The fastest plane flies at a ground speed 75 miles per hour faster than another.)
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If F flies at 450mph for 3 hours, then the distance is 1350
S flies for 3.6 hours at 375 (3.6 * 375) = 1350
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Sort of a convoluted problem!  I'm sure there are many ways to solve it.  This is just one.