I don't understand this question, can someone please help me out? Thank you!

Municipal bonds are currently offering investors a 10% return and corporate bonds

with the same maturity and default risk are offering investors a 12% return. Municipal

bonds are exempt from personal income tax while corporate bonds are not.

(a) What is the after-tax return on municipal bonds for an investor in the 30% personal

income tax bracket?

(b) What is the after-tax return on corporate bonds for an investor in the 30% personal

income tax bracket?

(c) At what personal income tax rate would an investor be indifferent between corporate

bonds and municipal bonds?