Senior two writes college entrance examination mathematics.

There are three situations that can be solved:

1. Boy A is on the left of the three boys. At this time, the other two boys had a 2/2 arrangement. A There must be a group of girls on the left. The girls are divided into two groups and ranked among the boys, so there is A2/2 * (C2/3 * A2/2) * C1/2 * C1/3 = 70.

There are 72 kinds of the same boys.

3. Among the three boys, team A has A2/2 (C2/3 * A2/A) * A2/4 =144.

So there are 288 kinds of * * *

Winter vacation homework's Math Test Paper Practice in Luoshe Junior Middle School, Wuxi City, Jiangsu Province 1 1

What is the composition of correspondence in Suzhou University?

How can I become an excellent programmer? Even engineers

Examination methods of mathematics in grade three.

Shangliu Mathematics Volume 13

What does Monti Hall problem prove in advanced mathematical theory? Why can you prove it?

Are there any Japanese schools in America?

Do you think it's worthwhile for some people to get average grades in China, but their parents are willing to spend a lot of money to send them abroad to study?

Wang Lin, a math teacher

Educational significance of playing digital turntable with teaching AIDS