There are n cities. What is the number of airlines that connected 6 different cities (airline from city A to city B is different with airline from city B to city A)?  Choose the correct choice from the following answers.
A) n(n-5)  B) n(n+1)  C) n(n-1)/2  D) n(n+1)/2  E) n2
First of all, the possible number of airlines is n. Then, the possible number of airlines departing from one city to another becomes (n-5). Hence, the answer is n(n-5), which makes A an answer choice.   n(n-5)
<result>A</result>
There are n cities. What is the number of airlines that connected 6 different cities (airline from city A to city B is different with airline from city B to city A)?