Suppose three equally likely outcomes could happen one year from now: good, medium, and bad. Security A pays $$1$ if the good outcome happens and $$0$ otherwise. Security B pays $$1$ if the medium outcome happens and $$0$ otherwise. Security C pays $$1$ if the bad outcome happens and $$0$ otherwise.

Security A trades today for $$\mathrm{.}25$;

Security B trades today for $$\mathrm{.}30$;

Security C trades today for $$\mathrm{.}35.$

Using the Law of One Price, what is the risk$-$free rate?