Mary deposits $700 into a fund at the beginning of each year for 10 years. At the end of 15 years, she makes an additional deposit of X. At the end of 20 years, Mary uses the accumulated balance in the fund to buy a perpetuity-immediate with annual payments of $1400 per year for 10 years, and $1050 per year thereafter. Interest is credited at an annual effective rate of 4%. Calculate X. Answer = $ (round your answer to 2 decimal places.)