Three gentlemen and three ladies are candidates for two vacancies. A voter has to vote for two candidates. In how many ways can one cast his vote?
Choices:	A) 9	B) 30	C) 36	D) 15	E) None
Solution: There are 6 candidates and a voter has to vote for any two of them.   So, the required number of ways is,   = 6C2 = 6!/2!*4!   = 15.   Answer: Option 15
<result>D</result>
Three gentlemen and three ladies are candidates for two vacancies. A voter has to vote for two candidates. In how many ways can one cast his vote?