143k views
4 votes
Hello! I am really struggling with this question and it would be great to have some help!

Hello! I am really struggling with this question and it would be great to have some-example-1

1 Answer

4 votes

Solution:

Question:

How many ways can two teachers, four male students, five female students and one administrator be arranged if the teachers must sit together, the male students must sit together and the female students must sit together?

Step 1:

If the two teachers must sit together, they will be arranged in


2!ways

Step 2:

If the male students must sit together,they will be arranged in


4!ways

Step 3:

If the female students must sit together, they will be arranged in


5!ways

Step 4:

If they are to be arranged as a group along with the administrator, they will be arranged as


4!ways

Hence,

The number of ways in which they can be arranged will be given below as


\begin{gathered} 2!*4!*5!*4! \\ =2*1*4*3*2*1*5*4*3*2*1*4*3*2*1 \\ =138240ways \end{gathered}

Hence,

The final answer is


\Rightarrow138240ways

User Malsmith
by
3.7k points