Please solve this problem using EXCEL!!

Suppose you purchase a 30 -year, zero-coupon bond with a yield to maturity of 6%. You hold the bond for five years before selling it. a) If the bond's yield to maturity is 6% when you sell it, what is the internal rate of return of your investment? b) If the bond's yield to maturity is 7% when you sell it, what is the internal rate of return of your investment? c) If the bond's yield to maturity is 5% when you sell it, what is the internal rate of return of your investment? d) Even if a bond has no chance of default, is your investment risk free if you plan to sell it before it matures? Explain