Facebook just issued $$100$ million of $20-$year zero coupon bonds. These bonds are currently priced at $$225.$ In addition, Facebook has $$30$ million of Preferred Stock with a current market price of $$125$ per share and an annual dividend of $$10$ per share. Facebook has $$670$ million worth of common stock and just paid a dividend of $$3$ per share and it is expected that the dividends will grow at $4\%$ per year from now on$.$ Assume the market rate is $11\%,$ and the risk$-$free rate of return is $3\%.$ Facebook has a beta of $1\mathrm{.}5$ and a federal income tax rate of $21\%.$

What is the after$-$tax cost of Facebook debt?