A train overtakes two persons who are wal… | Answer

Subject

Quantitative Aptitude

Topic

Speed & Distance

A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph respectively and passes them completely in 9 and 10 seconds respectively. The length of the train is ______ metres.
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Explanation

Let the speed of the train be ‘x’ kmph and it’s length be ‘y’ km Case 1: Relative to person 1 ∵ the train and 1st person are travelling in the same direction, Relative speed = (x – 2) kmph Distance travelled by train in crossing the person = y km Time taken = 9 seconds = 9/3600 hrs But we know that, Distance = speed × Time ∴ y = (x – 2) × (9/3600) -----(1) Case 2: Relative to person 2 ∵ the train and 2nd person are travelling in the same direction, Relative speed = (x – 4) kmph Distance travelled by train in crossing the person = y km Time taken = 10 seconds = 10/3600 hrs But we know that, Distance = speed × Time ∴ y = (x – 4) × (10/3600) -----(2) ∴ on equating equations (1) and (2) we get,

\left( {{\rm{x}} - 4} \right){\rm{\;}} \times {\rm{\;}}\frac{{10}}{{3600}}{\rm{\;}} = {\rm{\;}}\left( {{\rm{x\;}}-{\rm{\;}}2} \right){\rm{\;}} \times {\rm{\;}}\frac{9}{{3600}}

∴ x = 22 kmph Substituting the value of x in equation (1) we get, Y = 50 meters Thus the length of the train is 50 meters

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A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph respectively and passes them completely in 9 and 10 seconds respectively. The length of the train is ______ metres.Reading

A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph respectively and passes them completely in 9 and 10 seconds respectively. The length of the train is ______ metres.

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A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph respectively and passes them completely in 9 and 10 seconds respectively. The length of the train is ______ metres.
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