Production plan with three departments

A firm produces three items. One unit of the first requires $2$ hours in department A, $1$ in department B and $1$ in department C; one unit of the second requires $1$, $3$ and $1$ hours; one unit of the third requires $1$, $2$ and $3$ hours. Departments A, B and C have $80$, $130$ and $80$ hours available. Find the quantities of the three items that use up all the available hours.