So, we know that for ever 100 digits, there are 10 digits that have a 0 in the one's place (100, 110, 120, 130, 140, 150, 160, 170, 180, and 190), and 9 different numbers with a 0 in the ten's place (101, 102, 103, 104, 105, 106, 107, 108, and 109). You do not count any number twice. That's 19/100. Now, that's an answer for ever 100, until you get to the 900's, since there's only 99 in that place.
We know there are 899 options, so that's our denominator. Then, 19+19+19+19+19+19+19+19+19=171.
Assuming that the equation is in the form , we can plug in points to get our equation. For ease, let's use (1,18) and (2,21). When plugging these points in, we get . Now let's divide the equations to get rid of : . Now that we have , we can plug in the value we just calculated to solve for : , and solving for , we get .
So the
This equation in decimal form (rounded to the nearest thousandth) is .