A bond issued by the State of New York offers an 8.4% tax-exempt yield. Assuming equivalent risk, what must Fred and Wilma Stoneftint receive from a corporate bond yield that would offer them a pre-tax yield equivalent to the State of New York's tax-exempt yield, assuming that the Stoneflint's are in the 24% marginal tax bracket? Assume further that a bond issued by Ford Motor Company yields 9.75%, at what marginal tax bracket would the be indifferent to owning the Ford Motor bond or a City of Newton tax-exempt bond yielding 6,63%, assuming equivalent risk and duration