85820 = Y + (Y x 1.25% + 30)
What's Y?
$$85820 = Y + (Y \times 1.25\% + 30)\\ 85820 = Y + Y \times 0.0125 + 30\\ 85790 = Y + Y \times 0.0125 \\ 85790 = Y \times 1.0125 \\ Y = 85790/1.0125$$
Y = 84730.86
