Find the gross profit of an item after taxation given its cost price and selling price.
Cost price: 50
Selling price: 100
Gross profit = 50, after taxation.
Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Find the gross profit of an item after taxation given its cost price and selling price.

### Response:
Gross profit = 50, after taxation.