Question

If y + 2q = 15, q + 2p = 5 and p + 2y = 7, then find
the value of p + q + y.

Answer 1

`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=(23)/(3)\\\\ y=15-2q=15-2((23)/(3))=15-(29)/(3)=15-7=8\\\\ p=7-2y\\ p=7-2*8\\ p=7-16=-9\\\\ \textbf{p+q+y=}-9+(23)/(3)+8=-1+7(2)/(3)=\boxed{6(2)/(3)}`