Calculate the discounted price of an item.
Regular Price: $100 
Discount Rate: 0.2
The regular price of the item is $100 and the discount rate is 0.2, which means the discount on this item would be $100 * 0.2 = $20. Therefore, the discounted price of the item would be $100 - $20 = $80.
Complete the following task based on the instruction and optional input provided.### Instruction:
Calculate the discounted price of an item.

### Input:
Regular Price: $100 
Discount Rate: 0.2

### Output:
The regular price of the item is $100 and the discount rate is 0.2, which means the discount on this item would be $100 * 0.2 = $20. Therefore, the discounted price of the item would be $100 - $20 = $80.