+0  
 
0
195
3
avatar

I have  different mathematics textbooks and  different psychology textbooks. In how many ways can I place the  textbooks on a bookshelf, in a row, if there must be a psychology textbook exactly in the middle, and there must be a mathematics textbook at each end?

 Apr 3, 2022
 #1
avatar
0

The number of ways is 5x4x4x3x3 = 720.

 Apr 3, 2022
 #2
avatar
+1

The 2 Math books at each end can be chosen in: 5C2 ==10 different ways

 

The psychology book in the middle can be chosen in: 4C1==4 different way

 

The remaining 6 books (3 math + 3 psychology) can be arranged in: 6! ==720 ways.

 

Therefore, the 9 books can be arranged in:10  x  4  x  720 ==28,800 ways.

 Apr 3, 2022
 #3
avatar+117849 
+1

Edit your question so that the whole thing is together and makes total sense.

 Apr 3, 2022

36 Online Users

avatar