“We can use some fancy math to predict how long the line will get,” Keely Croxton of Ohio State says, then apply it to related problems. In response to a listener request, “Marketplace” host Kai ...

The wait can feel endless. There you stand, an overflowing trolley, a screaming child behind you, and someone fumbling for coins ahead. The other lines seem to be moving through faster. Perhaps you ...

Let’s say you and your roommate have a little side business baking rhubarb pies at home and selling them on a street corner. Folks love pie, and you’re having trouble keeping up with demand. But you ...