5 digits makes up to 99,999
120
there are 5 ways
Two, if the order of the primes is ignored.
ask your face
120 ways.120 ways.120 ways.120 ways.
5
*facepalms* "Can you please repeat the question?"
362880 ways. 9!=9*8*7*6*5*4*3*2*1=362880
The answer is 7!/5! = 42 ways.
12!/(5!*7!)The number of ways to arrange nitems is n!, where "!" is the factorial function. The number of ways we can arrange the 12 books is therefore 12!. However, we don't really care what order the first 5 books are in, or what order the last 7 books are in, as long as they're the same books. We therefore divide by the number of ways to arrange 5 books and the number of ways to arrange 7 books.
5
The number of ways is 18C5 = 18!/(5!*13!) = 8,568 ways.