The answer is $0\mathrm{.}0336$ ft$^3/$s

Please explain

$14\mathrm{.}3$E The flow of kerosene is being measured with an orifice meter similar to that shown in Fig. $14\mathrm{.}6.$ The pipe is a $2-$in Schedule $40$ pipe and the orifice diameter is $1\mathrm{.}00$ in $.$ The kerosene is at $77F.$ For a pressure difference of $0\mathrm{.}53$ psi across the orifice, calculate the volume flow rate of kerosene.