10. Xiao Wang and Xiao Li both brought some money to buy the book "Harry Potter." When they arrived at the bookstore, it turned out that the money Xiao Wang brought was 6 yuan short of buying 2 books, and the money Xiao Li brought was 31 yuan short of buying 2 books. However, the money they brought together was just enough to buy 3 books. The price of each "Harry Potter" book is ( ) yuan.
【Analysis】When the two people's money is added together, they are 37 yuan short of buying 4 books, which is exactly the price of 3 books, so 1 book costs 37 yuan.