Assume both portfolios A and $B$ are well diversified, that $E(r_A)=15\mathrm{.}4\%$ and $E(r_B)=16\mathrm{.}3\%.$ If the economy has only one factor, and ${}_A=1$ while ${}_B=1\mathrm{.}1,$ What must be the risk$-$free rate? $($Do not round intermediate calculations. Round your answer to $1$ decimal place.$)$

Risk$-$free rate

$\%$