0.2 km/h^2 3.0 km/h^2 6.0 km/h^2 12.0 km/h^2
I gave my students this multiple choice question: Two bicyclists were riding their bikes at a rate of 20 kilometers per hour (km/h). During the next half hour, they observed that they had increased their speed to 26 km/h. What was their average acceleration?

Only one answer is correct among these 4 choices:
- 0.2 km/h^2
- 3.0 km/h^2
- 6.0 km/h^2
- 12.0 km/h^2

Could you tell me which one is correct?

12.0 km/h^2