Answer:
 Present value of annuity = 623,110.5 
Step-by-step explanation:
To determine present value of annuity of $50,000. 
Annuity is fixed series of cash flows for a definite time period. 
 present value of money at the time retirement is
Present value of annuity =
![Annuity * ([1 - (1 )/(( 1 + r)^(n))])/(r)](https://img.qammunity.org/2020/formulas/business/college/1nbpfjlx137uu2e008pvk1hp82d3a4cpkx.png)
 where,
n of year of payment left to receive
r =rate of interest
Present value of annuity =
![50,000 * ([ 1 - (1)/(( 1 + 0.05)^(20))])/(0.05)](https://img.qammunity.org/2020/formulas/business/college/hq4avxvg7nobtd24ot04502kem2olrf5c4.png) 
 
 Present value of annuity = 50,000 * 12.46221 
 Present value of annuity = 623,110.5