You have the following data for ABM Corp. The market value of assets is $$500$M$,$ and the market value of debt is $280$M$.$ The company is considering repurchasing its stock for $$20$M and issuing bonds for the same amount. This would move beta to $0\mathrm{.}99$ and yield to maturity on debt to $6\%.$ Estimate new WACC if risk$-$free rate is $3\mathrm{.}5\%$ and the return on stock market is $8\mathrm{.}2\%.$ The company pays $22\%$ taxes on its profits.

The correct Answer is $6\mathrm{.}1\%,$ please tell me the calculation.