Consider a 9-year bond with face value $1,000 that pays an 8.8% coupon semi-annually and has a yield-to-maturity of 6.5%. What is the approximate percentage change in the price of bond if interest rates in the economy are expected to decrease by 0.60% per year? Submit your answer as a percentage and round to two decimal places. (Hint: What is the expected price of the bond before and after the change in interest rates?)

(i) Describe and interpret the assumptions related to the problem.

(ii) Apply the appropriate mathematical model to solve the problem.

I NEED HELP WITH THESE TWO PARTS OF THE PROBLEM. I KNOW THE CALCULATIONS AND SOLUTION, BUT DON'T KNOW THIS PART.