\[ \begin{array}{l} \text { Maximize } W=250 y_{1}-540 y_{2}+600 y_{3} \\ \text { subject to } \\ 10 y_{1}-22 y_{2}+15 y_{3}=15 \\ 15 y_{1}+20 y_{2}+13 y_{3} \geq 29 \\ 1 \text { - } \\ -20 y_{2}+12 y