I'm trying to work this sum out,

A party was organized for thirty people at which they could have either a hamburger or a pizza. If there were five times as many hamburgers as pizzas calculate the number of each.

I've been trying to work out and answer for over half an hour now but so far I could only come up with

$\displaystyle x =$ number of pizzas

$\displaystyle y =$ number of hamburgers

Equation 1 :

$\displaystyle x+y=30$

Equation 2:

$\displaystyle 5x-y=0$

Is this correct?