Pure molar volumes of component $1$ and component $2$ are given as V$1=60$ cm$3/$ mol and V$2=120$ cm$3/$ mol at $40\backslash$deg C$.$ What is the vol$$me of mixture if $240$ cm$3$ of component $1$ is mixed with $720$ cm$3$ of component $2?$ The vol$$me change of the mixture at $40\backslash$deg C as a function of composition is given below.

$$V $=$ x$1.$ x$2.(65.$x$1+15.$x$2)($cm$3/$ mol$)$