$1.$ Suppose an investment bank has $$900$ billion in assets under management and a leverage ratio $($Assets $/$ Equity$)$ of $20$ to $1.$ If the bank earns $($annually$)$ a $7\%$ return on its assets and pays $4\%$ interest on its debt and the tax rate is $20\%,$ what is the $($annual$)$ return$-$on$-$equity?