[tex]y+2q=15\\
y=15-2q\\\\
p+2y=7\\
p+2(15-2q)=7\\
p+30-4q=7\\
-3q+30=7\ \ \ |Subtract\ 30 \\
-3q=-23\ \ \ |Divide\ by\ -3\\
q=\frac{23}{3}\\\\
y=15-2q=15-2(\frac{23}{3})=15-\frac{29}{3}=15-7=8\\\\
p=7-2y\\
p=7-2*8\\
p=7-16=-9\\\\
\textbf{p+q+y=}-9+\frac{23}{3}+8=-1+7\frac{2}{3}=\boxed{6\frac{2}{3}}
[/tex]
