calculus
posted by ujkk .
When air expands adiabatically (without gaining or losing heat), its pressure P and volume V are related by the equation PV^{1.4}=C where C is a constant. Suppose that at a certain instant the volume is 380 cubic centimeters and the pressure is 89 kPa and is decreasing at a rate of 10 kPa/minute. At what rate in cubic centimeters per minute is the volume increasing at this instant?

PV^k=C
take the derivative
kPv^(k1) dV/dt+V^k dP/dt=0
solve for dV/dt
dV/dt= V/Pk * dP/dt check that.