Two receipts of $$1,000$ each are desired at the end of years $3$ and $4.$ Given that interest rates are $8\%,8\mathrm{.}5\%,9\%$ and $10\%$ for years $1,2,3$ and $4$ respectively, determine the equal payment amount made at the end of years $1,2$ and $3$ that is equivalent to those two receipts. Sketch the appropriate cash flow and outline your calculations clearly. Adding an excel sheet that supports your calculations is advantageous.