2 men and 3 women are lined up in a row. What is the number of cases where they stand with each other in turn? (The number of cases in which men (or women) do not stand next to each other)  Pick one
A) 12 B) 15 C) 18 D) 21 E) 24
First arrange 3 women. 3 women can be arranged in 3 places in 3! ways. Now   W Blank W BlankW   we have to fill the two blanks with 2 men. We can arrange 2 persons in 2 places in 2! ways.   3! * 2! = 12 ways.   12 is the answer
<result>A</result>
2 men and 3 women are lined up in a row. What is the number of cases where they stand with each other in turn? (The number of cases in which men (or women) do not stand next to each other)