Dianna has 6 quarters 5 dimes and 4nickles in her purse. she reaches into her purse and randomly grabs two coins. what is the probability that diana grabs two dimes

First of all, we know that Dianna has total 6+5+4=15 coins including: 6 quarters, 5 dimes and 4 nickles in her purse.
P(grabbing the first dimes):
5/15 or 1/3
P(grabbing the second dimes):
5/15 or 1/3
P(grabbing 2 dimes in a row):
1/3*1/3=1/9. As a result,the probability that Diana grabs 2 dimes is 1/9. Hope it help!