We know that:
[tex]P_{1}V_{1}= P_{2}V_{2}[/tex] .......(1)
Given at [tex]P_{1}=30cm^3[/tex] , [tex]V_{1}=10^5Pa[/tex]
a)
When [tex]P_{2}=2*10^5Pa[/tex] , [tex]V_2=[/tex]?
Using equation (1)
[tex]30*10^5=2*10^5*V_2[/tex]
[tex]V_2=30/2=15cm^3[/tex]
b)
When [tex]P_2=5*10^5Pa[/tex], [tex]V_2=?[/tex]
using equation (1)
[tex]30*10^5=5*10^5*V_2[/tex]
[tex]V_2=30/5=6cm^3[/tex]