please do not do in excel , thank you (:

14.2 Ex-Post Cost of Borrowing. Many firms in many countries borrow at nominal costs that later prove to be very different. For example, Deutsche Bank recently borrowed at a nominal cost of 9.59% per annum, but later that debt was selling to yield 7.24%. At the same time, the Kingdom of Thailand bor- rowed at a nominal cost of 8.70% but later found the debt was sold in the market at a yield of 11.87%. What caused these changes, and what might manage- ment do to benefit (as Deutsche Bank did) rather than suffer (as the Kingdom of Thailand did)