I come up with $19,266.67
Do you need to see my steps?
This is Linda and here are the detailed step.
Discount Amount = 20000 x 11% x (120/360) = 733.33
So Proceed = 20000-733.33 = 19266.67
If you need any further information please let me know. You can request me in future by writing "FOR LINDA" in your post.