In order to watch this solution you need to have a subscription.
This is Giancoli Answers with Mr. Dychko. The car has an initial speed of 28 meters per second and a final speed of zero because it comes to rest and it takes 8 seconds for it to slow down from 28 to 0 meters per second and the question is over what distance does it travel during this time? So we have this formula that says distance is average speed times time and so we put in the initial or the final velocity, I should say, zero plus the initial of 28 divided by 2 and then times by 8 seconds and that gives 112 meters covered while it is decelerating.