Benjamin went to a bookstore and purchased a variety of books. He bought 5 copies of a sci-fi novel, each priced at $20, 3 copies of a history book priced at $30 each, and 2 copies of a philosophy book for $45 each. What was the total cost of his purchases?

The total cost of Benjamin ' s purch ases is : \n \n 5 copies of sci - fi novel x $ 2 0 / copy = $ << 5 \ * 2 0 = 1 0 0 1 0 0 \n 3 copies of history book x $ 3 0 / copy = $ << 3 \ * 3 0 = 9 0 9 0 \n 2 copies of philosophy book x $ 4 5 / copy = $ << 2 \ * 4 5 = 9 0 9 0 \n \n Total cost = $ 1 0 0 + $ 9 0 + $ 9 0 = $ << 1 0 0 + 9 0 + 9 0 = 2 8 0 2 8 0 . </s>