a train 140 meters long takes 6 seconds to cross a man walking at 5 kmph in the direction opposite to that of the train. find the speed of the train.	Choose one.
A) 45 kmph B) 50 kmph C) 55 kmph D) 60 kmph E) 79 kmph
<gadget id="calculator">10 / 36</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">6 * (5/18)</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">140 / (5/3)</gadget>
<output>84</output>

<gadget id="calculator">84 - 5</gadget>
<output>79</output>

<result>E</result>
a train 140 meters long takes 6 seconds to cross a man walking at 5 kmph in the direction opposite to that of the train. find the speed of the train.
subtract(divide(140, multiply(6, const_0_2778)), 5)
"explanation : let the speed of the train be x kmph . speed of the train relative to man = ( x + 5 ) kmph = ( x + 5 ) × 5 / 18 m / sec . therefore 140 / ( ( x + 5 ) × 5 / 18 ) = 6 < = > 30 ( x + 5 ) = 2520 < = > x = 79 speed of the train is 79 kmph . answer : option e"