$0\mathrm{.}015m^3$ of gasoline $($A$)$ was spilled on an area of $1\mathrm{.}80m2.$ Find the time $($h$)$ taken for all of the

spilled gasoline to evaporate into the air $($B$).$ Ignore the humidity of the air $($Dry air$).$ Diffusion

coefficient DAB$=1\mathrm{.}68*{10}^{-4}\frac{m^2}{s}.$

Evaporation takes place within a $15cm$ film layer at $20C.$ The vapor pressure of gasoline at this

temperature is $13\mathrm{.}79$kPa. Ignore the concentration of gasoline in the air beyond $15cm.($The density

of gasoline is $\{$:$719\frac{kg}{m^3})*(R=0\mathrm{.}08206(atm)*L*mo{l}^{-1}*K^{-1})$