Question 473454: how many ways can 5 pictures be selected from 10 pictures. if the order they are selected is important Answer by Theo(13342) (Show Source):
You can put this solution on YOUR website! the formula is nPx = n! / (n-x)!
n = 10
x = 5
the formula becomes 10P5 = 10 ! / 5! which equals 10*9*8*7*6*5!/5!.
the 5! cancels out and you are left with 10*9*8*7*6 which is equal to 30240.
To see how this works, assume you want to select 2 pictures out of 3 pictures.
the formula would be 3P2 = 3! / 1! = 6
Assume the pictures are labeled a, b, and c.
your possible permutations are:
ab
ba
ac
ca
bc
cb
