Answer
$1.80\times10^5V$.
Work Step by Step
Use equation 17–5 to find the potential of a point charge.
$$V=\frac{1}{4\pi\epsilon_o}\frac{Q}{r}$$
$$V=(8.99\times10^9\frac{N\cdot m^2}{C^2})\frac{3.00\times10^{-6}C}{1.50\times10^{-1}m}$$
$$=1.80\times10^5V$$