Given,
The initial temperature of the room, T₁=20 °C=293.15 K
The final temperature, T₂=40 °C=313.15 K
Let the initial temperature of the room be P₁, and the final temperature be P₂
From Gay-Lussac's law,
On substituting the known values in the above equation,
Therefore P₂ is given by,
Therefore, the new pressure relative to the initial pressure is 1.07 times the initial pressure, i.e., 1.07P₁