A cylinder fitted with a sliding piston contains a volume of ideal gas V$,$ which exerts a pressure P on the piston. The gas expands slowly, pushing the piston upward. The relationship between P $($in bar$)$ and V $($in cubed meters$)$ durring this expansion is $P(V^{1\mathrm{.}2})=0\mathrm{.}223.$ Calculate the work done $by$ the gas $asit$ expands from $an$ initial colume $of0\mathrm{.}03$ meters cubed to a final volume of $0\mathrm{.}1608$ meters cubed. The answer key shows the answer should be $64$ kJ$.$ I need help getting to that answer $.$