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 = $<<65*10/100=6.50>>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=8.50>>8.50 profit after the discount.

Therefore, the percent profit is $8.50/$50 x 100% = <<8.5/50*100=17>>17%.

# Answer

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<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
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?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
17
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?
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