Question

A combination lock has 6 different numbers. If each number can only be used ONCE, how many different combinations are possible?

Answer 1

A 'number' can be 0,1,2,3,4,5,6,7,8,9
There are ten options for each number.
If there are 6 numbers, there are 10^6 different combinations.

Answer 2

151200 possible combinations

Explanation:

There are 10 digits 0 - 9 ( 0,1,2,3,4,5,6,7,8,9)

There are 10 choices for the first digit

10

There are 9 choices for the second digit

9

There are 8 choices for the third digit

8

and so on since we can only use each digit once

10 *9*8 *7 *6*5

151200 possible combinations