(3 11/15 + y) - 5 7/15 = 3 4/15

(56/15 + y) - 5 7/15 = 3 4/15

(56/15 + y) - 82/15 = 3 4/15

(56/15 + y) - 82/15 = 49/15

56/15 + y - 82/15 = 49/15

- 26 + y = 49/15

y = 49/15 + 26/15

y = 75/15

y = 5

Ответ: y = 5