There are 16 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 the correct choice:
A) 288	B) 267	C) 261	D) 211	E) 306

Rationale: the total number of stations = 18 from 18 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 18 p ₂ ways . 18 p ₂ = 18 * 17 = 306 . answer : e
Answer: E