$30-$inch corrugated metal pipe$($s$),90-$ft long, with a $3\mathrm{.}5\%$ slope are to be used for a road crossing over a small drainage channel that carries the flow for a watershed with the following components:

$27$ acres of woodlands

$35$ acres of suburban residential areas

$18$ acres of business areas

Based on the information above determine:

A$)$ the peak runoff from a $60-$min, $2-$yr storm event $($use the IDF curve for Bluefield, WV$)$

B$)$ determine how many $)=(\mathrm{.}025$ pipes are needed to carry the storm flow if it is desired that each pipe only flows at half full.