Solution:
\[\begin{array}{*{35}{l}}
~P1\text{ }=\text{ }1\text{ }bar \\
P2\text{ }=\text{ }? \\
~V1=\text{ }500\text{ }dm3 \\
V2=200\text{ }dm3 \\
\end{array}\]
As temperature stays steady at 30°C,
\[\begin{array}{*{35}{l}}
P1V1=P2V2 \\
~ \\
1\text{ }bar\text{ }x\text{ }500\text{ }dm3\text{ }=\text{ }P2\text{ }x\text{ }200\text{ }dm3\text{ }or\text{ }P2=500/200\text{ }bar=2.5\text{ }bar \\
\end{array}\]