Styrene is produced by catalytic dehydrogenation of ethyl- benzene at high temperature in the presence of superheated steam. (a) Find ÄH°rxn, ÄG °rxn, and ÄS °rxn, given these data at 298 K: (b) At what temperature is the reaction spontaneous?

What are Delta G and K at 600 degrees?

I only need help with K at 600 degrees. I thought it was 9.9 x 10^2 but it was marked wrong.
Data:
Ethylbenzene,
C6H5--CH2CH3 :

delta Ht = -12.5 kJ/mol,
delta Gt = 119.7 kJ/mol
and S = 255 J/mol*K

Styrene,
C6H5--CH==CH2 :

delta Ht = 103.8 kJ/mol,
delta Gt = 202.5 kJ/mol
and S = 238 J/mol*K

thank you. I only need help with K at 600 degrees.