We know that work done by the gas is given as

ΔW=PΔV

From graph we can write

V_A =V_C = 10cc=10×10^-6m³

V_D=V_B = 25cc= 25×10^-6m³

P_B=P_C=30kPa= 30×10³Pa

P_A=P_D=10kPa=10×10³Pa

Work done in path ADB W_ADB=W_AD + W_DB

W_ADB = P_A (V_D-V_A) + 0 (∵ W_DB =0 because V_D=V_B)

=10×10³×(25-10)×10^-6

=0.15J

Work done in path AB W_AB= P_avg(V_B-V_A)

W_AB=20×10³× (25-10)×10^-6

=0.30J

Work done in path ACB W_ACB= W_AC+W_BC

W_ACB = 0+P_B(V_B-V_C) (∵ W_AC=0 because V_A=V_C)

=30×10³×(25-10)×10^-6

=0.45J