$3-64$E$.$ For the pump in Figure $3-43,Q_{\text{o}\text{u}\text{t}}=30gpm$ of oil having a specific gravity of $0\mathrm{.}9.$ Points A and $B$ are at the same elevation. What is $Q_{in}?$ Assuming the pump efficiency is $100\%,$ find the pressure difference between points A and $B$ if

a$.$ The pump is turned off

b$.$ The input power to the pump is $2$ hp