constant acceleration problem

hi,

I'm having a bit of trouble with the concept of constant acceleration.

*If a car goes from 0 to 80 mph in six seconds with constant acceleration, what is that acceleration?*

My initial thought was to take the change in velocity (80mph) and divide it by the change in time (6s). But I'm not really sure what constant acceleration means.

the answer should be in ft/sec^2. I tried converting everything to ft and sec, but I still couldn't get the right answer. Plz help . thank you.