Answer:
1/22
Step-by-step explanation:
First off we have a total of 12 letters. Of these we have 3 vowels. So the chance to pick a vowel is 3/12 or 1/4.
Next we don't replace the tile, so we have a total of 11 tiles left. There are two tiles with the letter R, so we have a 2/11 chance to pick those.
Thus total chance is 1/4 * 2/11 = 2/44 = 1/22
