Related rates implicit differentiation?

When air expans adiabatically 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 310 cubic cenitmeters and the pressure is 97 kPa and is decreasing at a rate of 15 kPa/minute. At what rate in cubic centimeters per minute is the volume increasing at this instant?