show steps do not use excel. I need to understand the process behind this.

An estate sets up a trust to fund different charities. Each year, the fund will provide a payment of $10,000 at the end of each year to a selected charity. The fund earns an annual effective rate of interest of 5%. If the fund is to pay out in perpetuity, what must be the present value of the estate (i.e. find the present value of a perpetuity with payments of $10,000 and an interest rate of 5%). Suppose that charity A receives the payments in years 1, 4, 7, ...: charity B receives the payments in years 2, 5, 8, ... and charity C receives the payments in years 3, 6, 9, ... .Determine the proportion of the estate that will be paid to charity B