Word problem solve using a system of two equations

[Kriston]

There are quarters and dimes in a box. Their total value is $5.40. Quarters are five times as many as dimes. How many quarters and how many dimes are in the box?

I use the following variables and I'm trying to solve by using system of two equations

x= quarters
y= dimes

I think I have the first equation, but not sure how to do the rest or even if the first equation is correct.
5x+y=5.40

 

[BigGlenntheHeavy]

\(\displaystyle .25Q+.10D \ = \ 5.40\)

\(\displaystyle \frac{D}{Q} \ = \frac{1}{5}, \ \implies \ Q \ = \ 5D, \ Q-5D \ = \ 0\)

\(\displaystyle Solve \ the \ system.\)