The farthest distance Nicole rode in a day during her training for a bike race was 20 miles.
To determine the farthest distance Nicole rode in a day, we need to consider the list of daily distances she has tracked. The numbers you've provided, presumably represent the distances she's trained for during different days. Our task is simply to identify the maximum value from this list.
The distances you've mentioned are: 0 miles, 4 miles, 12 miles, 16 miles and 20 miles. Looking at these figures, the farthest Nicole rode in a day is 20 miles. Since this distance is greater than all the other distances, it represents the longest training session she had.