Question

at a given tempature gas with a pressure of 150 kpa has volume of 0.8 l if the pressure decreases to 75kpa and the temperature remains the same what will be the volume of the gas

Answer 1

  P*V/T=constant 
so P*V= constant*T 
if T doesn't change then 
P*V= constant 
so 150kPa*0.8L=75kPa*xL 
xL=150kPa*0.8L/75kPa=1.6L 
hope it help