Question:
A light ray emerging from the point source placed at $\mathrm{P}(1,3)$ is reflected at a point $\mathrm{Q}$ in the axis of $x$. If the reflected ray passes through the point $\mathrm{R}(6,7)$, then the abscissa of $\mathrm{Q}$ is :
Correct Option: , 4
Solution:
