Puzzle of the Week for 14 December 1998

Jeremy's family is on their way to the toy store. They've parked next to the bakery, and all of them start from the same point at the same time. Jeremy, being particularly eager to get to the toy store, runs down the sidewalk at 2 meters per second (saying "Hurry!" once per 10 meters), while the rest of his family follows him at 1 meter per second (saying "Wait!" once per 5 meters).

When Jeremy reaches the front door of the toy store, he sees one of those irritating signs that say "Children must be accompanied by an adult" (which he reads instantaneously), so he immediately turns around and runs back to his family. When he reaches his family, he turns and runs back to the front door of the toy store. He continues running back and forth until he meets his family 10 meters from the door of the toy store, after having made three round trips.

How far is the bakery from the toy store? (Assume that Jeremy loses no time while changing direction, and runs at 2 meters per second in both directions.)