Answer : The correct option is, (C) 120 L
Explanation :
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,

where,
= initial pressure of gas = 0.50 atm
= final pressure of gas = 1.2 atm
= initial volume of gas = ?
= final volume of gas = 48 L
= initial temperature of gas = 325 K
= final temperature of gas = 320 K
Now put all the given values in the above equation, we get:


Therefore, the initial volume was 120 L.