Assuming that 9898 has no "repeating" digits.
The first digit cannot be 0, so there are nine choices, 4 even and 5 odd.
For the second digit we have nine choices. If the first digit is even then we have four even and five odd choices, otherwise five even and 4 odd. Total is 81 choices, 41 even and 40 odd.
For the third digit we have nine choices. Again four even and five odd choices if the second is even, five even and 4 odd otherwise. Total 729 choices, 364 even and 365 odd.
The last digit must be even. So we have four choices if the third is even and five choices if the third is odd. Total 4x364 + 5x365 = 9x364 + 5 = 3281.
x2 + y2 = r2
where x,y are the coordinates of each point and r is the radius of the circle.
time = i/(pr)
= 11,200 / 4,800
= 2.33 or 2 years and 4 months