The ideal gas law formula is: PV=nRT. As the n(moles of gas), R(Gas constant) and T(temperature) values are constant as it is given in the problem, we can calculate the pressure difference by the following formula: xΔP(difference factor of pressure)=1/xΔV. We can find the difference factor of volume by x=V(0)/v(1),
x=18l/2l=9 which means the pressure is 9 times greater after the volume is down to 2l. To find the final pressure, we can use P(1)=xP(0), when we add the numbers in, it looks like this: P(1)=9*42 kPa=378 kPa
