Posted by Elizabeth on Monday, December 10, 2012 at 10:16am.
A motorist makes a journey of 240 km from Singapore to Malacca to visit his inlaws at an average speed of x kilometers.
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/x6 is the time it takes for the return journey.
What do I do next? Please help!

Math  Steve, Monday, December 10, 2012 at 10:31am
and you know that the return journey takes 1/3 hour longer than the one going.
240/x + 1/3 = 240/(x6)
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 10:32am
oops. typo that's
3(1±√481)

Math  Elizabeth, Monday, December 10, 2012 at 10:48am
thanks!

Math  ammar, Sunday, December 7, 2014 at 3:37am
dhek bhai phely minutes ko convert kro phir jo answer aye us ko 240se add kr k equation se agey solve krlo

Math  titu mir, Sunday, December 7, 2014 at 3:39am
galat galat ammar galat

Math  Anonymous, Monday, May 2, 2016 at 6:11am
kk thanks
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