Chapter 3 - Section 3.9 - Related Rates - 3.9 Exercises - Page 250: 37

The volume is decreasing at a rate of $80~cm^3/min$

$PV = C$ $V~\frac{dP}{dt}+P~\frac{dV}{dt} = 0$ $P~\frac{dV}{dt} = -V~\frac{dP}{dt}$ $\frac{dV}{dt} = -\frac{V}{P}~\frac{dP}{dt}$ $\frac{dV}{dt} = -\frac{600~cm^3}{150~kPa}~(20~kPa/min)$ $\frac{dV}{dt} = -80~cm^3/min$ The volume is decreasing at a rate of $80~cm^3/min$