Answer:
This can be done in 3,060 ways.
Explanation:
Letters are chosen without replacement, and the order does not matter, which means that the combinations formula is used.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.
![C_(n,x) = (n!)/(x!(n-x)!)](https://img.qammunity.org/2022/formulas/mathematics/college/mztppiaohythui2rvvokdfm636pzgsn6x6.png)
In this question:
Four letters from a set of 18. So
![C_(18,4) = (18!)/(4!14!) = 3060](https://img.qammunity.org/2022/formulas/mathematics/college/w7ii1x5njtntvb50r5cpxkprfdby1cvtcj.png)
This can be done in 3,060 ways.