Problem $6[15$ points$]$: Water at $20$

C flows through the $20-mm$ diameter galvanized iron pipe such that it discharges at C from the fully open gate valve $B$ at $0\mathrm{.}03\frac{m^3}{s}.$ Determine the required pressure at A and include all major and minor losses $($at four elbows and a gate valve$).$ The roughness coefficient for GI pipe is given in previous problem.