Problem $1.$ Psychrometric processes $(4$ points$)$

Must provide both calculation process and psychrometric chart $($uploaded on Canvas$)$ with marks

of return air, outdoor air, mixed air, and supply air.

$1-1)$ A stream of $10,000$ CFM of return air at $75F$ dry bulb temperature and $60\%RH$ is flowing

by a return fan. $60\%$ of return air from a space is exhausted to outside and $40\%$ of return air is

recirculated and adiabatically mixed with $10,000$ CFM of outdoor air at $45F$ dry bulb temperature

and $40F$ thermodynamic wet bulb temperature. Find the airflow rate $(CFMorf\frac{t^3}{m}in),$ dry bulb

temperature, humidity ratio, and enthalpy of the resulting mixed air? $(60\%)$