To calculate 20 days, 15 hours, and 0 minutes into the future, you can start by converting the days and hours to minutes. There are 1,440 minutes in a day (24 hours x 60 minutes), so 20 days would be 20 x 1,440 = 28,800 minutes. Adding the 15 hours is another 900 minutes. The total would be 29,700 minutes into the future.