solution:
Leave the volume of the round lined cup alone V.
Then, at that point, the volume of air inside the cup at 27° C is V.
Presently,
\[\begin{array}{*{35}{l}}
~ \\
V1\text{ }=\text{ }V \\
~ \\
T1\text{ }=\text{ }27{}^\circ C\text{ }=\text{ }300\text{ }K \\
~ \\
V2\text{ }=? \\
~ \\
T2\text{ }=\text{ }477{}^\circ \text{ }C\text{ }=\text{ }750\text{ }K \\
\end{array}\]
As per Charles’ law,