The reaction

C4H8(g)āŸ¶2C2H4(g)

has an activation energy of 262 kJ/mol.
At 600.0 K,
the rate constant, ,
is 6.1Ɨ10āˆ’8 sāˆ’1.
What is the value of the rate constant at 805.0 K?

I get 0.052739 and apparently it's wrong. Please work the problem out in great detail.