A 20-year annuity X has annual payments of $10,000 at the beginning of each year for 10 years, then annual payments of $20,000 at the beginning of each year for the next 10 years. A perpetuity Y has payments of Q at the end of each year for 10 years, then payments of 2Q at the end of each year thereafter. The present values of X and Y are equal when calculated using an annual effective interest rate of 5%. Find Q.