The following pressures and cumulative production

data are available for a natural$-$gas reservoir:

$($a$)$ Estimate the initial gas$-$in$-$place.

$($b$)$ Estimate the recoverable reserves at an abandon$-$

ment pressure of $500$ psia. Assume $z_a=1\mathrm{.}00.$

$($c$)$ What is the recovery factor at the abandonment

pressure of $500$psia $?$