Find the price which should be paid for an annuity of 500 per year for the next 10 years, if the yield rate is to be 11% and if the principal can be replaced by a sinking fund earning 8% per year for the next 6 years and 7% for the following 4 years after that.

I know the answer should be 2760.22 but I am unsure as to how to get there

note: please do not use excel to solve, I need a written solution.