Consider the reaction: 2NO2 (g) ? N2O4 (g)

Calculate ?G at 298 K if the partial pressures of NO2 and N2O4 are 0.36 atm and 1.64 atm, respectively.

I used ?G= -RT(lnK)
K= (1.64 atm) / (0.36 atm)^2 = 12.65
R= 8.314
?G= -(8.314)(298K)ln(12.65) = -6287.23

The answer calls for 1 sig fig (online homework) so I put -6000, but got it wrong..then I noticed it has to be in kJ, so i put -6 & still got it wrong. What am I doing wrong here? Anybody help? Thanks!

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