You are tasked to see how debt financing impacts equity required return for TTA Inc. The levered Beta is $1\mathrm{.}30$ and tax rate is $40\%.$ The total market value of the firm $($Debt and Equity$)$ is $$900,000,000,$ with debt $$600,000,000$ so equity is the remainder.

c$.$ Find the D$/$E ratio

d$.$ Find the unlevered Beta for TTA.