Assume no taxes or other frictions. Manufacturing Master Inc. MMI is an established manufacturing firm with a steadily growing free cash flow. In particular, the free cash flow next year year is expected to be $ million, and subsequent growth is expected to be a year perpetually. The free cash flow is all paid out. Currently year MMI is all equity financed, with a cost of capital of The riskfree interest rate is for all maturities.

MMI now decides to issue a new debt to buy back part of its equity. The new debt takes the form of a consol bond, paying $ million per year forever. The new debt is riskfree, given MMIs future cash flows.

QUESTION : Next year year after the payout to its equity and debt holders, what is MMIs debt to equity ratio?

I got the answer but the correct answer

please give me a step by step calculation, how to get an answer  this is kinda tricky question.