SOLUTION: A car travelled from Kago to Agra at an average speed of 60kmlh and returned at 45km/h on the Same Route. If the total time taken for the joumey was 3hours 30minutes. Find the dist

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Question 1207363: A car travelled from Kago to Agra at an average speed of 60kmlh and returned at 45km/h on the Same Route. If the total time taken for the joumey was 3hours 30minutes. Find the distance between Kaga and Agra.
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
.
A car travelled from Kago to Agra at an average speed of 60kmlh and returned at 45km/h
on the Same Route. If the total time taken for the joumey was 3hours 30minutes.
Find the distance between Kaga and Agra.
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           Method 1 - using time equation


Let "d" be one way distance, in kilometers.

Then the time moving from K to A is  d%2F60  hours;

     the time moving from A to K is  d%2F45  hours.


Total time is 31%2F2  hours;  so we write this "time equation"

    d%2F60 + d%2F45 = 31%2F2.


To solve it and to find "d", multiply both sides by 180. You will get

    3d + 4d = 630

       7d   = 630

        d   = 630/7 = 90.


ANSWER.  The distance is 90 km.



           Method 2 - using distance equation


Let "t" be one the travel time from K to A, in hours.

Then the travel time back is 3.5-t hours.


The distance from K to A is  60t kilometers.

The distance from A to K is  45(3.5-t) kilometers.

The distance is the same, so we write this distance equation

    60t = 45(3.5-t).


Simplify and find t

    60t = 45*3.5 - 45t

    60t + 45t = 45*3.5

       105t   = 45*3.5

          t   = %2845%2A3.5%29%2F105 = 1.5.


Thus, the travel time from K to A is 1.5 hours - hence, the distance is 1.5*60 = 90 kilometers.

You get the same answer.

Solved in two ways - for your better understanding.



Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


To add to the response from tutor @ikleyn, here is another, very different method for solving the problem.

The ratio of the two speeds is 60:45 = 4:3. Since the distances are the same, the ratio of times at the two speeds is 3:4.

So 3/7 of the total time was at 60km/h and 4/7 of the time at 45km/h.

(3/7) of 3 hours 30 minutes = (3/7) of 210 minutes = 3*30 minutes = 90 minutes = 1 hour 30 minutes.

1 hour 30 minutes at 60km/hr is 90km.

ANSWER: 90km