In a subtraction formula, the sum of the subtracted, the subtracted and the difference is 1800, and the difference is 19 times that of the subtracted. What is the difference?

In a subtraction formula, the sum of the subtracted, the subtracted and the difference is 1800, and the difference is 19 times that of the subtracted. What is the difference?

1800 / 2 = 900 sum of subtraction and difference
900 / (19 + 1) = 45 minus
900-45 = 855 difference