An ESP is treating $150,000f\frac{t^3}{m}in$ of air with an effective drift velocity of $20f\frac{t}{m}in.$

a$)$ Calculate the total plate area $($in $f{t}^2)$ required to achieve $95\%$ efficiency in an ESP by using the mixed$-$flow equation.

b$)$ Assuming the plates are $20-ft$ high and $10-ft$ long, and that there will be $3$ sections in the direction of flow, calculate the number of plates required.