Open book examination $($No notes allowed even if written on the book$)$

Question $1$:

Water $($A$)$ at $25C$ is flowing in a covered irrigation ditch below ground. Every $30m,$ there is a vent line with a $25mm$ Inside diameter and it is $1m$ long to the outside atmosphere at $25C.$ There are $10$ vents in the $300-m$ ditch. Calculate the total evaporation loss of water in $k\frac{g}{?}$ day if the air is humid $($not dry$),$ and the percentage relative humidity, i$.$e$.\%RH=100(\frac{p_A}{p_A^0})=30\%,$ where $p_A$ is the partial pressure of the water vapor in the air and $p_A^0$ is the vapor pressure, Assume $p_{BM}$~$=1$