In the $1980$s$,$ U$.$S$.$ banks offered All$-$Saver Certificates for a one$-$year term. The interest rate on these certificates was $70\%$ of the contemporaneous one$-$year U$.$S$.$ Treasury Note rate. One year Treasury Notes were yielding $15\mathrm{.}37\%(!).$ Although there was no limit to the amount of All$-$Saver Certificates you could hold, only $$1,000$ of annual interest was exempt from Federal taxation per individual. a$)$ What was the rate on All$-$Saver Certificates? What was the maximum amount an individual could invest and still have all the interest exempt from taxation? b$)$ Compute the marginal tax rate of an individual who would be indifferent between investing the amount computed in $($a$)$ in All$-$Saver Certificates or in $1-$year Treasury Notes. $($Assume no divisibility problems.$)$ c$)$ What would be the dollar gain for an individual in the $50\%$ marginal tax bracket who invested the am