Figure shows two blocks in contact sliding down

Figure shows two blocks in contact sliding down an inclined surface of inclination $30^{\circ}$. The friction coefficient between the block of mass $2.0 \mathrm{~kg}$ and theincline is $\mathrm{p}$ and that between the block of mass $4.0 \mathrm{~kg}$ and the incline is $\mu$. Calculate the acceleration of the $2.0 \mathrm{~kg}$ block if $(\mathrm{a}) \mu 1=0.20$ and $\mu 2=0.30$, (b) $\mu 1=0.30$ and $\mu 2=0.20$. Take $g=10 \mathrm{~m} / \mathrm{s}^{2}$.