Answer
$-0.27 L/s$
Work Step by Step
Apply the chain rule: $\dfrac{dV}{dt}=(\dfrac{\partial V}{\partial P})(\dfrac{dP}{ dt})+(\dfrac{\partial V}{\partial T})(\dfrac{dT}{dt})$
or, $=(-8.31)\dfrac{T}{P^2})(\dfrac{dP}{ dt})+8.31(\dfrac{1}{P})(\dfrac{dT}{dt})$
or, $=(-8.31)[-\dfrac{320}{(20)^2}) \times (0.05)+(\dfrac{1}{ 20})(0.15)]$
or, $ \approx -0.27 L/s$
