Answer: why Annie made the changes she did
Step-by-step explanation:
The first sentence stated that "Finally, on June 25, 1894, she was off". The sentence along with the second sentence doesn't give information regarding the reason for Annie made the changes that she made.
The sentence three stated that "It had taken her three months to travel approximately 1,300 miles, and she had more than 20,000 miles left to cover".
Without the writer not including the statistic in sentence 3, it'll have been unclear why Annie made the changes she did.