A perfect gas ( 0.1 mol ) having $\overline{\mathrm{C}}_v=1.50 \mathrm{R}$ (independent of temperature) undergoes the above transformation from point 1 to point 4 . If each step is reversible, the total work done (w) while going from point 1 to point 4 is ( -$)$ $\_\_\_\_$ J (nearest integer) $\left[\right.$ Given: $\left.\mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right]$