Mole fraction of both the gases:
Mole fraction of [tex] CCl_{4} [/tex]= [tex] \frac{Moles of CCl_{4}}{total moles} [/tex]
Mole fraction of [tex] CCl_{4} [/tex]= [tex] \frac{16}{16+4}=\frac{16}{20} = 0.8 [/tex]
Mole fraction of [tex] CCl_{4} [/tex]= [tex] \frac{Moles of CCl_{4}}{total moles} [/tex]
Mole fraction of dioxane = [tex] \frac{moles of dioxane}{total moles} [/tex]
Mole fraction of dioxane = [tex] \frac{4}{16+4}=\frac{4}{20} = 0.2 [/tex]
Total pressure of the solution is given by:
mol fraction of [tex] CCl_{4} [/tex] [tex] \times  [/tex] partial pressure of [tex] CCl_{4} [/tex] + mol fraction of dioxane [tex] \times  [/tex]  partial pressure of dioxane
Equating the values in the above equation:
Total pressure of the solution is:
= 0.8[tex] \times [/tex] 100 mmHg + 0.2 [tex] \times [/tex] 38 mmHg
= 87.6 mmHg