Methane gas contains carbon disulfide vapor in an amount such that the relative saturation at $35C$ is

$85\%.$ To what temperature must the gas mixture be cooled to condense out $60\%$ of the dislufide? The

total pressure is constant at $750mmHg$ and the vapor pressure of carbon disulfide is given by the

following relation: $P_{C{S}_2}^{**}=15\mathrm{.}47T+130,$ where $P_{C{S}_2}^{**}=$ vapor pressure of carbon disulfide in $mm$

$Hg$ and $T=$ temperature in degrees Centigrade.