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| Answer: 30 kmph and 6 kmph. |
| It is simple question based on the realation speed, time and distance. |
| Let us assume the boat is going with a speed 'b' kilo meters per hour (kmph in short) |
| and river is flowing at a speed of 'r' kmph. |
| [In our context speed and velocity are used as synonyms. |
| As per definition, speed means it will have magnitude, but no direction. |
| Velocity means it will have both magnitude and direction.] |
| The boat when going down stream, goes with higher speed, that is the sum of speeds, (b+r) kmph. |
| The boat when going up stream, goes with reduced speed, that is the difference of speeds, (b-r) kmph. |
| [Here boat should have more speed compared to river, otherwise boat can’t go to its destination.] |
| Now framing the equations: |
| Distance by speed gives time or Distance by time gives speed. |
| So 24/(2/3) = b+r -------- (1) [when 40 minutes is converted to hours, we get 40/60=2/3] |
| Similarly 24/1 = b-r ---------- (2) |
| After solving the equations, we get 2b = 60; implies b = 30 kmph. |
| When substituted in equation 2, we get r = 6 kmph. |
| This can be done converting all values into meters and seconds. |
| I received answers from many in meters and seconds. |
| [kmph can be converted to meters/sec by multiplying with a factor 5/18, |
| which is evaluated as shown below. 1km/hr = 1000 meters/3600 seconds= 5/18m/sec] |
| Winners:Raghu Ayinapurau, Bharadwaj Ainapurapu, Sumanth Nethi. |
| (Not considering this question for points as I posted the question at a random time.) |
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