How would I calculate rate of acceleration in this situation?

I am trying to do a study guide for my college level science exam that includes some physics questions. One particular question has to do with acceleration. I know how to generally calculate acceleration (change in time/change in velocity or force/mass). However, this particular question is driving me bonkers.



Here is the question:



Under the conditions just described, what is the acceleration of the cart?



The cart weighs 750g combined weight (it has a fan attached to the top and the weight includes both fan and cart). The fan can bring the cart to a speed of 1.2 m/s in 3 seconds. We are pretending there is no friction involved whatsoever.





Can someone please help me figure out how to solve this? Even if it's simple, it's driving me nuts and my exam is tomorrow! Thanks!How would I calculate rate of acceleration in this situation?
A = delta V / delta t = 1.2 m/s / 3 sec = 0.4m/(s*s)How would I calculate rate of acceleration in this situation?
I ain't that smart really to figuure this out.................good luck