A stream of air $(21$ mol$\%$ oxygen, the rest nitrogen$)$ flowing at a rate of $25$ kg$/$h is

mixed with a stream of carbon dioxide. The carbon dioxide enters a mixer at a rate of $40\mathrm{.}0$

m $3/$h at $200\backslash$deg C and $2$ bar absolute$.$ What is the mol $\%$ of carbon dioxide in the product

stream?