SOLUTION: a car traveling 60 km/h and return at 80km/h, talking a total journey of 5hr:30min for the total journey. how manykilometres does it travel altogether?

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Question 1143107: a car traveling 60 km/h and return at 80km/h, talking a total journey of 5hr:30min for the total journey. how manykilometres does it travel altogether?
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let  d  be one way distance (in kilometers).


Then the time to travel "to there"  is  d%2F60 hours, while the time travel back is  d%2F80  hours.


The total time is 5 hours and 30 minutes, or  51%2F2  hours = 11%2F2 hours.


It gives you the "time" equation

    d%2F60 + d%2F80 = 11%2F2   hours.


To solve the equation, multiply both sides by 240. You will get


    4d + 3d = 1320,

    7d       = 1320

     d       = 1320/7 = 188.57 km.


The two ways distance is  2*188.57 = 377.14 kilometers.    ANSWER


CHECK.  188.57%2F60 + 188.57%2F80 = 5.5 hours.   ! Correct !


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Using  "time"  equation is the  STANDARD  method of solving such problems.
From this lesson,  learn on how to write,  how to use and how to solve a  "time"  equation.

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