If one mole of a monoatomic gas ($\gamma = \large\frac{5}{3}$) is mixed with one mole of a diatomic gas ($\gamma = \large\frac{7}{5}$) . The value of V for the mixture is :

Question

$(a)\;1.4\qquad(b)\;1.5\qquad(c)\;1.53\qquad(d)\;3.07$