To answer this question, we have to determine the number of miles that Kim rode her bicycle per week, and the number of miles Eric rode per week.
We are given that Kim rode her bicycle 135 miles in 9 weeks, therefore, she rode:

Eric rode his bicycle 102 miles in 6 weeks, therefore, he rode:

Finally, we can conclude that Eric rode 2 more miles per week than Kim rode.
Answer: Eric rode 2 more miles per week than Kim rode.