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An airplane must fly from airport A to airport B, a distance of w km, and return.
During the first 2 hours it travels at k km per hour. At what rate must it travel
the remaining distance to complete the trip in 4 more hours?
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The entire two-ways trip is 2w kilometers long (w kilometers from A to B and w kilometers back).
In 2 hours, the airplane travels 2k kilometers; the remaining trip is 2w-2k kilometers.
It should be covered in 4 hours, so the average rate to travel the remaining distance
is = kilometers per hour. ANSWER
Solved.