Question

You have mixed up your locker combination again! You know it has the numbers 9, 7 and 23, but you are not sure of the order. What is the probability you get it open on the first try?

Answer 1

Probability of success on first try: `1/6`

Explanation:

There are 3 choices for the first number
...and for each of those there are 2 choices for the second number once the first one has been chosen
......and only 1 choice for the third number once the first two have been chosen.

Therefore there are `3xx2xx1=6` possible combination choices of which only `1` is correct.