Step-by-step explanation:

Answer:
I am thinking it is 112° or 136°
Let me know which one. Hope it helps though =)
"n choose k" gives you the number of possible unique combinations...
n!/(k!(n-k)!)
n=number of elements to choose from and k=the number of elements that you choose...in this case:
7!/[2!(7-2)!]
7!/[2!5!]
21
There are 21 possible different two question combinations that she can pick.
Answer:
I am pretty sure that $15.50 is the answer
Since, it is not given how many coins did Erica buy at the coin show, so, we can suppose that Erica bought "n" coins from the coin show.
Now, we know that Erica already had 6 coins in her coin collection before she went to the coin show and bought the "n" coins.
Therefore, the total number of coins that Erica will have in her possession after buying "n" coins from the coin show will be 6+n.