问题
单项选择题
In how many arrangements can a teacher seat 3 girls and 3 boys in a row of 6 seats if the boys are to have the first, third, and fifth seats ？（）
A.6
B.9
C.12
D.36
E.720
答案
参考答案：D
解析：
若3男孩在1，3，5时，则3个女孩应在2，4，6，所以总的安排方式为
。