Compute the total cost after applying the given tax rate.
Purchase price: $100
Tax rate: 9%
The tax amount will be 9% of $100, which is $9. When you add this to the original purchase price, the total cost comes out to be $100 + $9 = $109.
Complete the following task based on the instruction and optional input provided.### Instruction:
Compute the total cost after applying the given tax rate.

### Input:
Purchase price: $100
Tax rate: 9%

### Output:
The tax amount will be 9% of $100, which is $9. When you add this to the original purchase price, the total cost comes out to be $100 + $9 = $109.