To buy a book, you pay $20 for each of the first 5 books at the supermarket, and for each additional book you buy over $20, you receive a discount of $2. If Beatrice bought 20 books, how much did she pay at the supermarket? Give me reasons, before answering the question
For the first five books, the total cost is $20 * 5 = $100. For every additional book over $5, you pay $2 less, totaling to $20 - $2 = $18. Beatrice bought 20 books, so the number of books at which she received the $2 discount is 20 - 5 = 15 books. For the 15 books, Beatrice paid 15 * $18 = $270. In total, Beatrice paid $100 + $270 = $370 for the 20 books. So the final answer is 370.