Answer:
0.14% probability of a person guessing the right combination
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
The order in which the numbers are selected is important. For example, 1,3,2 is a different combination than 3,1,2. So we use the permutations formula to solve this question.
Permutations formula:
The number of possible permutations of x elements from a set of n elements is given by the following formula:
[tex]P_{(n,x)} = \frac{n!}{(n-x)!}[/tex]
Desired outcomes:
One right combination, so [tex]P = 1[/tex]
Total outcomes:
10 numbers from a set of 3. So
[tex]P_{(10,3)} = \frac{10!}{(10-3)!} = 720[/tex]
What is the probability of a person guessing the right combination?
[tex]p = \frac{D}{T} = \frac{1}{720} = 0.0014[/tex]
0.14% probability of a person guessing the right combination