\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
A delivery company delivers two types of packages. Let \(X\) be the number of small packages delivered and \(Y\) the number of large packages. If the delivery cost is \(\dollar 5\) per small package and \(\dollar 12\) per large package, which variable models the total delivery cost?