The pressure $P$ and volume $V$ of an expanding gas are related by the formula $PV^{b} = C$, where $b$ and $C$ are constants (this holds in adiabatic expansion, without heat gain or loss).

Find $\frac{dP}{dt}$ if $b= 1.2$, $P = 11 \textrm{kPa}$, $V = 70 \textrm{cm}^2$, and $\frac{dV}{dt} = 80 \textrm{cm}^3/\textrm{min}.$

$\frac{dP}{dt} =$ $\textrm{ kPa}/\textrm{min}$