A rod of length L is composed of a uniform length L/2 of wood whose mass is $M_w$  and a uniform length L/2 of brass whose mass is  $M_b$

The moment of inertia of rod about an axis passing through the centre and perpendicular to it is  $\frac{1}{12}{M}_w{L}^2$

 The moment of inertia rod about an axis passing through the centre and perpendicular to it is  $\frac{1}{12}\left(M_w+M_b\right)L^2$

The moment of inertia of rod about an axis passing through the wood end and perpendicular to the rod is   $\frac{1}{3}\left(M_w+M_b\right)L^2$

The moment of inertia of rod about an axis passing through the wood end and perpendicular to the rod is $\frac{1}{12}\left(M_w+7M_b\right)L^2$