Seven years ago XYZ International issued some 31-year zero-coupon bonds that were priced with a market's required yeild to maturity of 12 percent and a par value of $1,000. What did these bonds sell for when they were issued? b/ Now that 7 years have passed and the market's rquired yeild to maturity on these bonds has climbed to 14%,what are the selling for? c. if the market's required yeild to maturity had fallen to 10% what would they ahve been selling for?