有一道題目不太懂，有大大可以教我一下嗎...先謝了
A $100,000 par value bond with 8% annual coupons will be redeemed at 110% by payments of $5,000
at the end of years 5, 6, 7, 8, 9 and at par by payments of $10,000, $11,000, $12,000, $13,000,
$14,000, $15,000 at the end of years 10, 11, 12, 13, 14, 15, respectively. Calculate the purchase price of
the entire loan to obtain a net effective yield of 8% per annum if the investor is liable to tax at
25% both on interest and on capital gains.

我不太明白為何可以redeem above par 同時又可以redeem at par....這題是serial bond嗎? 感謝各位的解答...