(1 целая 4/15 - 1/5) * х = 1 целая 1/15 : 16
(1 целая 4/15 - 3/15) * х = 16/15 : 16
1 целая 1/15 * х = 16/15 * 1/16
16/15 * х = 1/15
х = 1/15 : 16/15
х = 1/15 * 15/16
х = 1/16
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Проверка: 1 целая 1/15 * 1/16 = 16/15 : 16
16/15 * 1/16 = 16/15 * 1/16
1/15 = 1/15