A sample of propane ($C_3{H}_8$) has a volume of $30{cm}^3$ at room temperature and pressure. The sample is burned completely in $1200{cm}^3$ of air. The final mixture is cooled to room temperature and pressure. The equation for the complete combustion is: $\text{C}_3\text{H}_8(g) + 5\text{O}_2(g) \rightarrow 3\text{CO}_2(g) + 4\text{H}_2\text{O}(l)$ Calculate the total volume of gas in the final mixture. Assume that air contains $21\%$ by volume of oxygen.