a cargo-loading problem, there are four items of different per unit weight and value as given below. The minimum cargo load is restricted to 10 units. How many units of each item are loaded to maximize the value?

\begin{tabular}{|c|c|c|} \hline Item & Weight wi & Value per unit vi \\ \hline 1 & 2 & 2 \\ \hline 2 & 3 & 5 \\ \hline 3 & 4 & 7 \\ \hline 5 & 5 & 9 \\ \hline \end{tabular}