Answer : The temperature of the gas is, 43.4 K
Explanation :
The expression used for work done will be,

where,
w = work done = 200 J
n = number of moles of gas = 0.40 mol
R = gas constant = 8.314 J/mole K
T = temperature of gas = ?
= initial volume of gas = X
= final volume of gas = 
Now put all the given values in the above formula, we get :


Thus, the temperature of the gas is, 43.4 K