https://www.williamsburgbridgemarathon.com/

From the race website:

"The 2024 Williamsburg Bridge Marathon will be a random distance between 10 and 40 miles.

Shortly after the race begins, organizers will generate a random number between 10 and 40. This number will be published X*4.5minutes after the start time of the race.

Example: if the selected distance is 32, the announcement will be posted online 144 minutes after the start of the race."

What will the random distance be?