Bookstore Sale Equation Representation

A bookstore is having a sale where customers can buy novels and biographies at a discount. The price of a novel is $12, and the price of a biography is $15. A customer buys a total of 10 books and pays $120. If the total number of novels bought is represented by the variable $x$ and the number of biographies by $y$, which of the following equations represents this scenario?

Additionally, the customer states that they bought twice as many novels as biographies. This relationship can be expressed with the equation $x = 2y$. Using this information, determine the correct equation that corresponds to the customers' purchases.