Okay, here are the steps to solve this problem:
* Taner ran 900 meters on each of 3 days. So in total Taner ran 900 * 3 = 2700 meters.
* Jaylen ran 1.2 kilometers on each of 2 days. So 1.2 km = 1200 meters. And 1200 * 2 = 2400 meters.
So in total:
Taner ran 2700 meters
Jaylen ran 2400 meters
Taner ran 2700 - 2400 = 300 more meters than Jaylen last week.
Therefore, Taner ran farther last week, by 300 meters.