SOLUTION: Denmark bikes the 36km to the resort averaging a certain speed. the return trip is made at a speed 3kph slower. the total time for the roundtrip is 7 hours. find Denmark's averagde
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-> SOLUTION: Denmark bikes the 36km to the resort averaging a certain speed. the return trip is made at a speed 3kph slower. the total time for the roundtrip is 7 hours. find Denmark's averagde
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Question 1119567: Denmark bikes the 36km to the resort averaging a certain speed. the return trip is made at a speed 3kph slower. the total time for the roundtrip is 7 hours. find Denmark's averagde speed on each part of the trip. Answer by ikleyn(52817) (Show Source):
Let x be the slower speed in kilometers per hour.
Then the faster speed is (x+3) km/h.
The time equation is
+ = 7. ( <<<---=== each fraction in the left side is the time, spent to cover 36 kilometers
with the corresponding speed).
To solve it, multiply both sides by x*(x+3); then simplify and solve the quadratic equation.
Answer. The slower speed is 9 km/h; the faster speed is 12 km/h.
Check. + = 4 + 3 = 7 hours.
