$=\int \frac{\mathrm{RTdV}}{\mathrm{V}^3}$

$=\mathrm{RT} \int_2^4 \mathrm{~V}^{-3} \mathrm{dV}$

$=8 \times 300 \times\left(-\frac{1}{2}\left[\frac{1}{4^2}-\frac{1}{2^2}\right]\right)$

$=225 \mathrm{~J}$

$\mathrm{~W}_{\mathrm{BC}} =\mathrm{P} \int_4^2 \mathrm{dV}=10(2-4)=-20 \mathrm{~J}$

$\mathrm{~W}_{\mathrm{CA}} =0$

$\therefore \mathrm{W}_{\text {cyck }} =205 \mathrm{~J}$

Note: Data is inconsistent in process $A B$.

So needs to be challenged.