There are 18 stations between Ernakulam and Chennai. How many second class tickets have to be printed, so that a passenger can travel from one station to any other station?
Choose the correct choice from the following choices
A) 800 B) 380 C) 360 D) 478 E) 566
The total number of stations= 20   From 20 Stations we have to choose any two stations and the direction of travel (Ernakulam to Chennai is different from Chennai to Ernakulam) in 20P2 ways.   20P2= 20*19= 
<gadget id="calculator">20*19</gadget>
<output>380</output>
380   ANSWER:380
<result>B</result>
There are 18 stations between Ernakulam and Chennai. How many second class tickets have to be printed, so that a passenger can travel from one station to any other station?