Can anyone help with a physics problem?

The equation for acceleration is change in velocity (speed) over change in time. Using this equation, I came up with -0.3 as my answer. This seems extremely incorrect, and I just wanted to double check it. The question is... Sophia is riding her tricycle at -4.5 km/hr when she begins pedaling faster to cause a... show more The equation for acceleration is change in velocity (speed) over change in time. Using this equation, I came up with -0.3 as my answer. This seems extremely incorrect, and I just wanted to double check it.

The question is...
Sophia is riding her tricycle at -4.5 km/hr when she begins pedaling faster to cause a constant acceleration. If, after 5.0 seconds, the tricycle is moving at -6.0 km/hr, what was the acceleration of the tricycle?
7 answers 7