Probably bad wording on my behalf (well, my course anyway

), but it isn't a "strip bond" value of 1800, it's 1800 + interest (at 11.5%). 1700.80 is what you would pay to get exactly 1800 at 11.5%. It should read "A debt of 1800, due in 6 months, bearing an interest rate of 11.5%" (paying in the original problem refers to interest payments being made, but is not an annuity, thus compounded.)

In either case, the value wouldn't be 1700.80 - the PV calc would have to work off the current value of money - in theory, one wouldn't pay 1700.80 if money was worth 13% (actual value of the FV 1700.80 in this situation is 1810.5). That is, someone could buy the exact same instrument at current rates to have 1810.50 rather than 1800 at 6 months. The 11.5% one would be discounted because of the change in interest rates.

(The question asks for the reference point being 9 months, but that's for the markers... should be the same answer either way, or extremely close.)