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April 17, 2014

April 17, 2014

Posted by **Elizabeth** on Monday, December 10, 2012 at 10:16am.

On his return journey, his average speed is reduced by 6km/hour due to traffic.

If the return journey takes 20 minutes longer, form an equation with x and solve it to find the average speed of each journey, giving your answer correct to two decimal places.

So: 240/x is the number of hours taken for the first journey.

240/x-6 is the time it takes for the return journey.

What do I do next? Please help!

- Math -
**Steve**, Monday, December 10, 2012 at 10:31amand you know that the return journey takes 1/3 hour longer than the one going.

240/x + 1/3 = 240/(x-6)

x = 3(1+±481) = 68.80

check:

240/62.80 = 3.82

240/68.80 = 3.49 = 3.82

difference: .33 hr = 20 min

you got the setup right, but didn't take that final step. Be sure to analyze**everything**they tell you, and the solution will emerge.

- Math -
**Steve**, Monday, December 10, 2012 at 10:32amoops. typo that's

3(1±√481)

- Math -
**Elizabeth**, Monday, December 10, 2012 at 10:48amthanks!

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