Help with Rate of Decay.

(1) The half-life for the radioactive decay of C-14 is 5730 years and is FIRST ORDER. How long will it take for 45.0% of the C-14 atoms in a sample of C-14 to decay?

Answer: log Ao/A = K*t/2.303 log 100%/55% = Kt/2.303

That's about as far as I get. I know I'm looking to solve for t. How do I go about that?