There are 17 stations between Hyderabad and Bangalore. How many second class tickets have to be printed, so that a passenger can travel from any station to any other station? Choose one:
A) 156  B) 167  C) 157  D) 342  E) 380
The total number of stations = 19   From 19 stations we have to choose any two stations and the direction of travel (i.e., Hyderabad to Bangalore is different from Bangalore to Hyderabad) in 19P₂ ways.   ²⁰P₂ = 19 * 18= 
<gadget id="calculator">19 * 18</gadget>
<output>342</output>
342.   Answer: 342
<result>D</result>
There are 17 stations between Hyderabad and Bangalore. How many second class tickets have to be printed, so that a passenger can travel from any station to any other station?