A train 100 m long passed a pole in 20 sec. How long will it take to pass a platform 500 m long?
Choose the correct choice from the following answers:
A) 90 sec  B) 100 sec  C) 110 sec  D) 120 sec  E) 130 sec
Speed = 100/20= 
<gadget id="calculator">100/20</gadget>
<output>5</output>
5 m/sec.   Required time= (100 + 500)/5= 
<gadget id="calculator">(100 + 500)/5</gadget>
<output>120</output>
120 sec   Answer:120 sec
<result>D</result>
A train 100 m long passed a pole in 20 sec. How long will it take to pass a platform 500 m long?