how many six letter words can be formed from the letters A,B,C,D,E,F, if each letter can only be used once?

Question

anonymous · Answer

720. If you want a detailed explanation, just read on

If you want the maximum number of possible combinations of those letters, you'll want to progressively multiply them together. It works like this:

Lets say the number of letters equals N and the total number of answers is X

by progressively multiplying we get:

X=N*(N-1)*(N-2)*(N-3)*(N-4)*...*1
so for N=6 (i.e. A,B,C,D,E&F) 
X=6*(6-1)*(6-2)*(6-3)*(6-4)*(6-5)
X=6*5*4*3*2*1
X=720

If you have a scientific calculator, you can easily calculate this by entering the number of letters (i.e. 6) and pressing the (x!) button