(9 * 13 + 9 * 2) / (54 * 3) = 9*(13 + 2) / (54 * 3) =
= (9 * 15) / (54 * 3) = (сокращаем 9 и 54, 15 и 3) = 5/6
(9 * 13 + 9 * 2) / (54 * 3) = 9*(13 + 2) / (54 * 3) =
= (9 * 15) / (54 * 3) = (сокращаем 9 и 54, 15 и 3) = 5/6