(Valuing bonds) Five years ago XYZ International issued some 30-year zero-coupon bonds that were priced with a market’s required yield to maturity of 8 percent. What did these bonds sell for when they were issued? Now that five years have passed and the market’s required yield to maturity on these bonds has climbed to 10 percent, what are they selling for? If the market’s required yield to maturity had fallen to 6 percent, what would they have been selling for?