Give the step-by-step reasoning process and then the final answer. 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?
The store made a $50 x 30 / 100 = $15 profit for selling it 30% above the cost. So, the book was sold for $50 + $15 = $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 = $58.50. There was $58.50 - $50 = $8.50 profit after the discount. Therefore, the percent profit is $8.50 / $50 x 100% = 17%.
The final answer: 17.