Toyota Corp's stock is $$25$ per share. Its expected return is $20\%$ and variance is $13\%.$ Honda Corp's stock is $$23$ per share. Its expected return is $16\%$ and variance is $4\%.$ Benz Corp's stock is $$42$ per share. Its expected return is $15\%$ and variance $5\%.$ The covariance between Toyota and Honda is $0\mathrm{.}08.$ What would be the standard deviation of a portfolio consisting of $50\%$ Toyota and $50\%$ Honda?