Let the P , V and n be the pressure ,volume ,no of moles respectively initialy.
T= 27c= 27 +273 K=300Kelvin
therefore according to ideal gas equation we can write
PV = n R T
PV = n r 300 (T= 300)
Now since 1/3rd gas escaped remaining gas = 2n/3
now let T'' = new temperature
PV = 2n/3 rT''
after putting value of n we get
PV = 2 PV/900r r T''
Now eliminating PV from both sides and r r canceled we get
T'' = 900/2 = 450 Kelvin = 450 -273=177 celcius
So ans 450 kelvin or 177 celcius