Question

PLEASE HELP! A suitcase lock has 3 dials with the digits 0, 1, 2,..., 9 on each. How many different settings are possible if all three digits have to be different?

Answer 1

504 settings. Factorial 

Answer 2

Digit 1: 1 number out of 10 total numbers = 1/10
Digit 2: 1 number out of 9 total numbers = 1/9
Digit 3: 1 number out of 8 total numbers = 1/8

Digit 1 AND Digit 2 AND Digit 3
1/10 x 1/9 x 1/8 = 1/720

Answer:
`(1)/(720)`