27/40 : 18 + 9/16 = 27/40 * 1/18 + 9/16 = 3/40 * 1/2 + 9/16 = 3/80 + 9/16 = 3/80 + 45/80 = 48/80 = 6/10 = 3/5
Ответ: 3/5