A train cross a 450 m bridge in 42 s and another bridge 650 m length in 50 s what is approximate speed of train in km/h? Choose the correct choice from the following choices
A) 90 Km /hr.  B) 25 Km /hr.  C) 30 Km /hr.  D) 20 Km /hr.  E) None of these
Explanation:   Let the length of the train be L.   Then,   =&gt; (450 + L)/42 = (650+L)/50.   =&gt; L= 600 m.   Now, speed = (450+600)/42 or  (650+600)/50= 
<gadget id="calculator"> (650+600)/50</gadget>
<output>25</output>
25 m/s i.e. 25*(18/5)= 90 Km /hr.   90 Km /hr.NSWER IS 90 Km /hr.
<result>A</result>
A train cross a 450 m bridge in 42 s and another bridge 650 m length in 50 s what is approximate speed of train in km/h?