20 i’m really confused can anyone ? ? 24) there are 10 digits on the keypad at an automated teller machine. how many four-digit passwords are available if no digit is repeated? 25) how many ways can yvette choose two greeting cards from 8 cards?

40320

Step-by-step explanation:

if you had a 1 digit number there will only be 1 possible combination for a 2 digit number there will only be 2 and for 3 there will be six if you find the pattern you will be able to see that the number of digits in the password is factorial numbers meaning that if you have 4 digits the solution to the problem would be:

4!

the ! after a number means that number multiplied by all the numbers below that all the way to 1

example:

4! = 4×3×2×1

so therefore if you have an 8 digit number the solution will be:

8!

which equals to:

40320

step-by-step explanation:

this is not a question

the correct option is b

step-by-step explanation: