I don’t understand the solution for question #17 on schweser, ss9 page 50.

If the question says interest rates fall to 8%, to calculate the value of the bond, wouldn’t you do,

n=50

fv=100

pv=?

i/y=4%

pmt=4?

so this means the bond is priced at par, pv=100

wouldn’t you take the 100 and compare it to the required asset once rates fell to 8%, in this case, $102? I just don’t get why they would use the current yield of 10%. I would think only the required rate and the rate the interest rate fell to were the only rates that mattered to answering question 17. On the blue box of page 34 on schweser, step 3, it looks like they used the immunized rate that it rised to (12%) and not the current immunized return (9%). Why is the solution solving this differently than page 32 or even the problems on the CFAI text?