Did I get this right?

Answer: Yes, the answer is 40 quarters.
Step-by-step explanation:
1. You need to remember that 4 quarters make a dollar.
2. Keeping this on mind, you can make a Rule of three, as following: If there are 4 quarters in 1 dollar, how many quarters are in 10 dollars?
Then:
4 quarters-------1 dollar
[tex]x[/tex]---10 dollars
[tex]x=\frac{(10dollars)(4quarters)}{1dollar}\\x=40quarters[/tex]
3. Therefore, there are 40 quarters in one roll.