In a certain province in France there are 15 cities. If a single road segment connects only two cities, how many road segments are required in order to connect the cities so that each city is connected to all other cities with a single road segment?  Answers
A) 30  B) 105  C) 330  D) 14!  E) 15!
1 city needs 14 roads to connect directly to the rest =&gt; 15 city needs 15*14 roads.   One road is counted twice =&gt; the number of road needed is 15*14/2= 
<gadget id="calculator">15*14/2</gadget>
<output>105</output>
105   Answer 105
<result>B</result>
In a certain province in France there are 15 cities. If a single road segment connects only two cities, how many road segments are required in order to connect the cities so that each city is connected to all other cities with a single road segment?