Harriet took 48 minutes to ride her bike the distance from her house to the town library. If she rode at a constant rate, what fraction of the total distance did she ride in the first 12 minutes?

This answer would be correct if Harriet had ridden for 16 minutes, not 12, because 16 minutes is one-third of 48 minutes. However, the question specifies that we are looking for the fraction of the total distance she rode in the first 12 minutes, which is only a quarter of the total time.

This is not correct because 1/2 of 48 minutes is 24 minutes. The question asks for the fraction of the total distance she rode in the first 12 minutes. Therefore, this option overestimates the proportion of the journey completed in the first 12 minutes.

This option would be correct if Harriet had ridden for 36 minutes because 36 minutes is three-quarters of 48 minutes. However, the question specifies that we want to know the fraction of distance she rode in the first 12 minutes. Hence, this answer significantly overestimates the proportion of the journey completed in the first 12 minutes.