Answer:

Step-by-step explanation:
We can solve the problem by using Gay-Lussac's law, which states that:
"For a fixed mass of ideal gas kept at constant volume, the pressure of the gas is directly proportional to its absolute temperature"
Mathematically:

where
p is the pressure
T is the absolute temperature
The equation can be also rewritten as

where, in this problem:
is the initial pressure
is the final pressure
is the final temperature
Solving for T1, we find the initial temperature:

Converted into Celsius degrees,
