The new pressure inside the piston is 3.43 atm
Calculation
The new pressure is calculated using Boyle's law formula
that is P1V1= P2V2 where,
P1= 2.00 atm
V1= 12.0 L
P2=?
V2= 7.00 L
make P2 the subject of the formula by diving both side by V2
P2 =P1V1/V2
P2= (2.00 atm x12.0 L) / 7.00L = 3.43 atm
