Australian AMC 2015 - Intermediate Question 9

Question 9

A packet of lollies contains 5 blue lollies, 15 yellow lollies and some red lollies.

One-third of the lollies are red. What fraction of the lollies are yellow?

$\frac13$
$\frac56$
$\frac12$
$\frac16$
$\frac23$