$($b$)$ A baghouse has been selected for particulate control. Estimate the number of bags required for a gas flow rate of $20\frac{m^3}{s}$ if each bag is $15cm$ in diameter and $12m$ in length. The air$-$to$-$cloth ratio $[$i$.$e$,$ the flow rate of air $\frac{m^3}{s}$ cloth area $(m^2))$ for the baghouse should be $0\mathrm{.}01\frac{m}{s}.$ At any given time, one$-$eighth of the bags are taken offline for cleaning.