Answer:
4/10 or .4 or 40 percent (I can't find the symbol for it)
Explanation:
we know that there are 10 letters that can be chosen from. there are 4 letters which we want to choose. the number of preferred outcomes /total outcomes = 4/10 or .4 or 40%.
I suggest that you use Khan academy and edpuzzle for this subject if you want a thorough explanation on how to do these.
if you have any questions, feel free to put them into the comments section below!