SOLUTION: A jet airplane departing on time flying between two airports at an average speed of 540 mph arrives eight minutes late. Departing on time and flying at an average speed of 480 mph

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Question 1043815: A jet airplane departing on time flying between two airports at an average speed of 540 mph arrives eight minutes late. Departing on time and flying at an average speed of 480 mph it arrives 53 minutes late. What is the number of miles between the two airports
Answer by ikleyn(52814) About Me  (Show Source):
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A jet airplane departing on time flying between two airports at an average speed of 540 mph arrives eight minutes late.
Departing on time and flying at an average speed of 480 mph it arrives 53 minutes late. What is the number of miles between the two airports
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Let D be the distance between the two airports.

First convert miles per hour into miles per minute.

480 mph = 480%2F60 = 80 miles-per-minute.
540 mph = 540%2F60 = 90 miles-per-minute.

Then your equation is

D%2F80+-+D%2F90 = 53 - 8 = 45.

Notice that D%2F80 it the time for the second scenario.
            D%2F90 is the time for the firs scenario.

Now solve this equation. It is easy.
As a first step, multiply both sides by 720, which is Least Common Multiple = Common Denominator.

Then you will be on a straight track.