The answers are 3/8 and 1/6.
There are 8 possible outcomes in the sample space for flipping 3 coins. Of those, 3 include two heads and 1 tail. This makes the probability 3/8.
Choosing a quarter for the first coin is 3/10, since there are 3 quarters out of 10 coins. After this, choosing a dime is given by 5/9, since there are 5 dimes out of 9 coins left:
3/10(5/9) = 15/90 = 1/6
