Scheduled payments of ​$1187​, ​$1148​, and ​$397 are due in one-and-a-half years​, four ​years, and six years respectively. What is the equivalent single replacement payment two-and-a-half years from...

Scheduled payments of ​$1187​, ​$1148​, and ​$397 are due in one-and-a-half years​, four ​years, and six years respectively. What is the equivalent single replacement payment two-and-a-half years from now if interest is 8.7 % compounded semi-annually ?