Nutrition A doctor recommends that a patient take 50 mg each of niacin, riboflavin, and thiamin daily to alleviate a vitamin deficiency. In his medicine chest at home, the patient finds three brands of vitamin pills. The amounts of the relevant vitamins per pill are given in the table. How many pills of each type should he take every day to get 50 $\mathrm{mg}$ of each vitamin?
$$\begin{array}{|c|cc|} \hline {} & {\text { VitaMax }} & {\text { Vitron }} & {\text { Vitaplus }} \\ \hline \text { Niacin (mg) } & {5} & {10} & {15} \\ {\text { Riboflavin (mg) }} & {15} & {20} & {0} \\ {\text { Thiamin (mg) }} & {10} & {10} & {10} \\ \hline\end{array}$$