Answer:
0.6 atm
Explanation:
We have a state change at a constant temperature. For isothermal transformations, Boyle proposed the equation:
P1V1 = P2V2 (Boyle's Law)
Where P1 and V1 are the pressure and the volume in the first state and P2 and V2 the pressure and the volume at the final state. So:
4x3 = 20xP2
20xP2 = 12
P2 = 0.6 atm