An ice cream truck is traveling through a neighborhood. Children from various homes have started chasing the truck and, by the time the truck has reached the end of the first street, there are 5 children it. On the second street, each child is joined by another child and on the third street, each child in the existing group is joined by another 2 children. The original 5 children then give up and leave the group. How many children are now following the truck?
Give me a detailed solution.