Answer:
Fiona has 6 quarters
Step-by-step explanation:
If Fiona were to have 1 quarter and 1+6 dimes she would have 8 coins
If she were to have 2 quarters and 2+6 dimes she would have 10 coins
If she were to have 3 quarters and 3+6 dimes she would have 12 coins
If she were to have 4 quarters and 4+6 dimes she would have 14 coins
If she were to have 5 quarters and 5+6 dimes she would have 16 coins
If she were to have 6 quarters and 6+6 dimes she would have 18 coins
Therefore, she has to have 6 quarters in order to have 6 more dimes and a total of 18 coins
I hope this helps, and I'm sorry it took so long for me to write this out
