Problem $2-11($LG $2-7)$

Suppose we observe the three$-$year Treasury security rate ${(}_1{R}_3)$ to be $4\mathrm{.}9$ percent, the expected one$-$year rate next year$-$E $(2^{r_1})-$ to be $5\mathrm{.}4$ percent, and the expected one$-$year rate the following year$-E(3r_1)-$to be $6\mathrm{.}4$ percent. If the unbiased expectations theory of the term structure of interest rates holds, what is the one$-$year Treasury security rate? $($Do not round intermediate calculations. Round your percentage answer to $2$ decimal places. $($e$.$g$.,32\mathrm{.}16))$

One$-$year Treasury security rate

Y $\%$