Question 1016678: The airplane flew m miles at r mph and arrived 2 hours late. How fast should the airplane have flown to have arrived on time? Any help is greatly appreciated!
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! airplane's speed is r, distance is m, time it took was m/r (units are miles/miles/hour, which is hours.
The time needed was (m/r)-2 hours. Over a common denominator of r, this is (m-2r)
The distance is unchanged at m
The time is (m-2r)/r
The speed is mr/(m-2r) ANSWER
Check with a plane that flies 200 mph for 6 hours (1200 miles) and should have been there in 4 hours.
The speed would then be 300 mph.
m=1200
r=200
mr=1200*200
(m-2r)=1200-400=800
mr/(m-2r)=1200*200/800=1.5*200=300mph.
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