Q: A train with a speed of 36 km/h and a length of 100 metres. Determine the time it takes for a man standing near a railway line to pass:  

<span class="pln">
</span><span class="typ">To</span><span class="pln"> solve </span><span class="kwd">this</span><span class="pln"> problem</span><span class="pun">,</span><span class="pln"> you can </span><span class="kwd">use</span><span class="pln"> the formula </span><span class="str">"distance = speed * time"</span><span class="pln"> to find the time it takes </span><span class="kwd">for</span><span class="pln"> the car to travel </span><span class="lit">100</span><span class="pln"> meters at a speed </span><span class="kwd">of</span><span class="pln"> </span><span class="lit">36</span><span class="pln"> km</span><span class="pun">/</span><span class="pln">hr</span><span class="pun">.</span><span class="pln">

</span><span class="typ">First</span><span class="pun">,</span><span class="pln"> you need to convert the speed </span><span class="kwd">from</span><span class="pln"> km</span><span class="pun">/</span><span class="pln">hr to m</span><span class="pun">/</span><span class="pln">s</span><span class="pun">.</span><span class="pln"> </span><span class="typ">You</span><span class="pln"> can </span><span class="kwd">do</span><span class="pln"> </span><span class="kwd">this</span><span class="pln"> </span><span class="kwd">by</span><span class="pln"> multiplying the speed </span><span class="kwd">by</span><span class="pln"> </span><span class="lit">1000</span><span class="pln"> </span><span class="kwd">and</span><span class="pln"> dividing </span><span class="kwd">by</span><span class="pln"> </span><span class="lit">3600.</span><span class="pln"> </span><span class="typ">This</span><span class="pln"> gives us</span><span class="pun">:</span><span class="pln"> </span><span class="lit">36</span><span class="pln"> km</span><span class="pun">/</span><span class="pln">hr </span><span class="pun">=</span><span class="pln"> </span><span class="lit">36</span><span class="pln"> </span><span class="pun">*</span><span class="pln"> </span><span class="lit">1000</span><span class="pln"> </span><span class="pun">/</span><span class="pln"> </span><span class="lit">3600</span><span class="pln"> </span><span class="pun">=</span><span class="pln"> </span><span class="lit">10</span><span class="pln"> m</span><span class="pun">/</span><span class="pln">s</span><span class="pun">.</span><span class="pln">

</span><span class="typ">Next</span><span class="pun">,</span><span class="pln"> you can plug the values </span><span class="kwd">into</span><span class="pln"> the formula to find the time it takes </span><span class="kwd">for</span><span class="pln"> the car to travel </span><span class="lit">100</span><span class="pln"> meters</span><span class="pun">:</span><span class="pln"> time </span><span class="pun">=</span><span class="pln"> </span><span class="lit">100</span><span class="pln"> m </span><span class="pun">/</span><span class="pln"> </span><span class="lit">10</span><span class="pln"> m</span><span class="pun">/</span><span class="pln">s </span><span class="pun">=</span><span class="pln"> </span><span class="lit">10</span><span class="pln"> seconds</span><span class="pun">.</span>