a train traveling at 72 kmph crosses a platform in 30 seconds and a man standing on the platform in 18 seconds. what is the length of the platform in meters? Choices.
A) 240 meters
B) 360 meters
C) 420 meters
D) 600 meters
E) can not be determined
<gadget id="calculator">72 * 1_000</gadget>
<output>72_000</output>

<gadget id="calculator">72_000 / 3_600</gadget>
<output>20</output>

<gadget id="calculator">20 * 30</gadget>
<output>600</output>

<gadget id="calculator">20 * 18</gadget>
<output>360</output>

<gadget id="calculator">600 - 360</gadget>
<output>240</output>

<result>A</result>
a train traveling at 72 kmph crosses a platform in 30 seconds and a man standing on the platform in 18 seconds. what is the length of the platform in meters?
subtract(multiply(divide(multiply(72, const_1000), const_3600), 30), multiply(divide(multiply(72, const_1000), const_3600), 18))
"explanation : length of the platform = speed of train * extra time taken to cross the platform . length of platform = 72 kmph * 12 seconds convert 72 kmph into m / sec 1 kmph = 518518 m / s ( this can be easily derived . but if you can remember this conversion , it saves a good 30 seconds ) . ∴ 72 kmph = 518 ∗ 72518 ∗ 72 = 20 m / sec therefore , length of the platform = 20 m / s * 12 sec = 240 meters . correct answer : a"