Jim decided to go for a drive in his car. He started out at 0 miles per hour (mph). He then

accelerated 20 mph down his street. Then, to get on the highway he accelerated another 35 miles

per hour. A car was going slow in front of him so he slowed down 11 mph. He then got off the

highway, so he slowed down another 7 mph. At what speed is he driving?