$\begin{align}  & q={{30}^{\circ }}\text{    }\!\!\{\!\!\text{ vertically opposite angles }\!\!\}\!\!\text{ } \\ & {{30}^{\circ }}+{{(p+2q)}^{\circ }}={{180}^{\circ }}\text{ }\!\!\{\!\!\text{ sum of }\angle s\text{ on a straight line }\!\!\}\!\!\text{ } \\ & {{30}^{\circ }}+p+2({{30}^{\circ }})={{180}^{\circ }} \\ & p={{90}^{\circ }} \\\end{align}$