I'm sorry but I'm not into square roots yet :(
It appears you are doing well. You have already gotten the eighth answer! If you need any other help you can ask me.
<span>Let the nickels be x and the dimes be y
x + y = 24
5x + 10y = 185
5x + 5y = 120
5y = 65
y=13
x=11
Answer: 11 nickels and 5 dimes</span>
D would be the highest value