Answer
$W = 2p_1V_1$
Work Step by Step
We know that:
$ W = \int p dV$
The area under the curve going from A to C is 0, so the gas does no work. We then find the work involved in going from C to B, which is given by the rectangular area under the curve.
$ W = (2p_1-0)*(2V_1-V_1)$
$W = 2p_1V_1$
