Two polaroids AandB are placed in such a way that the pass-axis of...

As given here, the pass axis of polaroids $A$ and $B$ are inclined at angle of $90 º$ with each other. Another polaroid $C$is placed at angle of $45 °$with respect to $A$ and $B$.

Therefore, intensity of light after falling on polaroid $A, {I}_{A} = \dfrac{{I}_{0}}{2}$

Intensity of light after falling on polaroid $C, {I}_{C} = {I}_{A}\cos^{2}45 ° = \dfrac{{I}_{0}}{2}\cos^{2}45 ° = \dfrac{{I}_{0}}{4}$

Intensity of light after falling on polaroid $B, {I}_{B} = {I}_{C}\cos^{2}45 ° = \dfrac{{I}_{0}}{4}\cos^{2}45 ° = \dfrac{{I}_{0}}{8}$