Question #$4$: New Chapter Two$-$Water Vapour, Evaporation and Precipitation $(15$ marks$)$

Given that a room has the dimensions of $20ft,15ft,$ and $10ft$ for its length, width, and height respectively, determine the mass and weight of the air in the room $($Assume that the room is filled with the moist air with the relative humidity of $RH=20\%$ at $p=101,325Pa$ and $T=20C.).$ Unit conversion: $1$ meter $=3\mathrm{.}28084ft.$ Hint: You need to calculate the density of the moist air from

${}_{ma}=\frac{p}{R_{da}T}(1-0\mathrm{.}378\frac{e}{p})$