A 600 meter long train crosses a signal post in 15 seconds. How long will it take to cross a 3 kilometer long bridge, at the same speed?
Answers:  A) 4 min  B) 2 min  C) 8 min  D) 9 min  E) 1.5 min
S = 600/15= 
<gadget id="calculator">600/15</gadget>
<output>40</output>
40 mps   S= 3600/40= 
<gadget id="calculator">3600/40</gadget>
<output>90</output>
90 sec= 1.5 min   Answer: 1.5 min
<result>E</result>
A 600 meter long train crosses a signal post in 15 seconds. How long will it take to cross a 3 kilometer long bridge, at the same speed?