She walked over many hills. Her average speed was faster during the first half of her walk. She walked in two different directions. She was walking at a constant speed.
I gave my students this multiple choice question: A girl walked for 30 minutes. She noticed that she traveled farther in the first 15 minutes of her walk than in the second 15 minutes. What can she conclude about her walk?

Only one answer is correct among these 4 choices:
- She walked over many hills.
- Her average speed was faster during the first half of her walk.
- She walked in two different directions.
- She was walking at a constant speed.

Could you tell me which one is correct?

Her average speed was faster during the first half of her walk.