24 ways
24 times
You can wind up with 10 different pairs of books in your hand, which you can choose from a shelf of 5 books in 20 different ways.
792 different groups of 5 books, in 95,040 different sequences.
6 ways
120. You do 5*4*3*2*1=120. you multiply the number that you are given for example how many times can books 3 be arranged on a shelf you multiply 3*2*1=6 that is your answer
There are 2*5! = 240 ways.
5 books can be lined up on a shelf in (5 x 4 x 3 x 2 x 1) = 120 different sequences.
There are seven books on the floor. Let x be the number of books on the floor. The number of books on the shelf is 2 + 3x. From the information given, 3x + 2 = number of books on the shelf. Substitute x=7 into 3x + 2 to find the answer. So, there are 23 books on the shelf.
240. 120 ways with the books stacked verticly, and 120 ways with the books stacked horizontaly, or one on top of the other.
it depends on the shelf of course
The number of ways that 15 books can be arranged on a shelf is the same as the number of permutations of 15 things taken 15 at a time. This is 15 factorial, or 15!, and is 1,307,674,368,000.
As many as the shelf's can hold or more but i think as many as the shelf's can hold.
The number of ways 7 different books can be stacked on a shelf is the same as the number of permutations of 7 things taken 7 at a time, which is 7 factorial, or 5040.