Solving for Average Acceleration: An Automotive Example

[ganon00]

was wondering which formula I would use to solve this equation...

a car traveling in a straight line has a velocity of +5.0m/s at some instant.
After 4.0seconds, it velocity is +8.0m/s. What is it average acceleration in this time interval?

 

[Hootenanny]

$$\bar{a} = \frac{\Delta v}{\Delta t}$$