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Let d be the distance between the two airports (in miles).
Flying at the speed of 540 mph, the airplane spends hours and arrives 8 minutes later.
Flying at the speed of 480 mph, the airplane spends hours and arrives 53 minutes later.
The difference of times is - hours.
From the other side, this difference is 53-8 = 45 minutes = of an hour = of an hour.
It gives you the "time" equation
- = .
At this point, the setup is just completed.
To find "d", multiply both sides of the equation (1) by 60. You will get
- = 45.
One more time, multiply both sides of the last equation by 72. You will get
9d - 8d = 72*45,
d = 3240
ANSWER. The distance between the two airports is 3240 miles.
CHECK. = 6.75 hours;
= 6 hours.
The difference is 0.75 of an hour = of an hour -- ! Correct !
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Using "time" equation is the STANDARD method of solving such problems.
It is simple, logical, straightforward and economic. Going in this way, you will not make a mistake - the logic of the method
prevents you of making mistakes.
From this lesson, learn on how to write, how to use and how to solve a "time" equation.
To see many other similar solved problems, look into the lessons
- Had a car move faster it would arrive sooner
- How far do you live from school? (*)
- Earthquake waves
- Time equation: HOW TO use, HOW TO write and HOW TO solve it
in this site.
For the TWIN problem, see the lesson (*) in the list.