Hello!
[tex]\large\boxed{a = 3m/s^{2}}[/tex]
Use the following equation to solve for the average acceleration of the motorcycle:
[tex]a = \frac{v_{f}-v_{i}}{t}[/tex]
Plug in the given final, initial velocities, and the time:
[tex]a = \frac{15-6}{3}\\\\a = \frac{9}{3}\\\\a = 3m/s^{2}[/tex]
