+0  
 
0
59
3
avatar

I have 7 different geometry textbooks and 4 different algebra textbooks. In how many ways can I place the 11 textbooks on a bookshelf, in a row, if there must be an algebra textbook in the middle, and there must be a geometry textbook at each end?

 Dec 18, 2019
 #1
avatar
0

The number of ways is 4*7*7*8! = 7902120.

 Dec 18, 2019
 #2
avatar
0

There are 7 ways to choose the geometry textbook at one end, then 6 ways to choose the geometry textbook at the other end.  Then there are 9 ways to choose the second textbook, 8 ways to choose the third textbook, and so on.  But then there are 4 ways to choose the algebra textbook, so there are 7*6*9!*4 = 60963840 ways that work.

 Dec 18, 2019
 #3
avatar+106519 
+1

See here, also  :

 

https://web2.0calc.com/questions/i-have-different-geography-textbooks-and-different

 

 

cool cool cool

 Dec 19, 2019

6 Online Users

avatar