find the average acceleration (m/s^2)

The formula is a=v2-v1/change in time
I don’t understand how to solve this since I only have the average time and distance in (m) for the marble

Please explain using steps I’m really stuck

2 answers

what do you mean by "average time?"
I had three times in seconds that I added then divided by 3 for the marble to come to a halt. I DONT KNOW HOW TO FIND THE AVERAGE ACCELERATION pLeAsE help this is due very soon