Farmer Xiao Li sells fruits, apples, pears, oranges, and peaches in a box at the farmers' market: three boxes of apples, pears, and oranges, with an average of 51 boxes; pears, oranges, and peaches with three boxes, average There are 47 boxes per box; two boxes of apples and peaches, with an average of 43 boxes. which is the total number of apples? ['1.', '5.', '9.', '3.']