Question

A lock has a 3-number code made up of 13 numbers. If none of the numbers are allowed to repeat, how many different ways can you choose three different numbers in order for a unique code?

Answer 1

Answer:

1716

Step-by-step explanation:

The first choice would be 1 of 13
The second choice would be 1 of 12 (it can't be the same as the first number since they don't repeat)
The third choice would be 1 of 11 (again, can't use the same number more than once)

That gives you 13*12*11=1716