Answer
$T_f = 348.1 K$ or $75.1 ^o C$
Work Step by Step
When the pressure is constant, we can use the $W = pΔV = nRΔT$ equation.
Now use the equation to solve for $T_f$
$W =nR(T_f-T_i)$
$\frac{W}{nR} + T_i =T_f$
$T_f = \frac{2400J }{(6) (8.314 J/mol.K)} + (27.0^o C + 273 K) $
$T_f = 348.1 K$ or $75.1 ^o C$