Below is an instruction that describes a task. Write a response that appropriately completes the request in English. Please answer in English.

### Instruction:
A store marks a book 30% above the cost. But during a sale, a 10% discount was given. If the book costs $50, what is the percent profit?

### Response:
The store made a $50 x 30/100 = $<<50*30/100=15>>15 profit for selling it 30% above the cost.
So, the book was sold for $50 + $15 = $<<50+15=65>>65.
During a sale, the book’s selling price decreased by $65 x 10/100 = $6.50.
So, the book was sold for $65 - $6.50 = $<<65-6.5=58.50>>58.50.
There was $58.50 - $50 = $<<58.5-50=8.5>>8.5 profit after the discount.
Therefore, the percentage profit is $8.5/$50 x 100% = <<8.5/50*100=17>>17%.
#### 17