There are 16 stations between Mumbai and Chennai. How many second class tickets have to be printed, so that a passenger can travel from any station to any other station?
Pick.
A) 316  B) 306  C) 326  D) 336  E) 356
The total number of stations = 18   From 18 stations we have to choose any two stations and the direction of travel (i.e., Mumbai to Chennai is different from Chennai to Mumbai) in 18P2 ways.   18P2= 18 * 17= 
<gadget id="calculator">18 * 17</gadget>
<output>306</output>
306   ANSWER: 306
<result>B</result>
There are 16 stations between Mumbai and Chennai. How many second class tickets have to be printed, so that a passenger can travel from any station to any other station?