Answer
$$0.040=4.0 \%
$$
Work Step by Step
In terms of $R=(B / A)^{2}$ , we can rewrite SWR as
$$
\operatorname{SWR}=\frac{A+B}{A-B}=\frac{1+(B / A)}{1-(B / A)}=\frac{1+\sqrt{R}}{1-\sqrt{R}} \Rightarrow R=\left(\frac{\mathrm{SWR}-1}{\mathrm{SWR}+1}\right)^{2} $$
$$\text { With } \mathrm{SWR}=1.50, \text { we obtain } $$
$$
R=\left(\frac{\mathrm{SWR}-1}{\mathrm{SWR}+1}\right)^{2}=\left(\frac{1.50-1}{1.50+1}\right)^{2}=0.040=4.0 \%
$$
