A bond maturing in december 2020 , 5% coupon, 6% interest, face value 4000, issued on Jan 1 2010.

So the N period is 11 totally or 10? if we find the book value at Jan 2011, the discount N period to maturity is 10 or 9?

So confused. in the Mock exam , it is only 9 period if find the book value at Jan 2011. Please add some comments