A Ten-Cent Brain Fart

I’m at work, and I notice that my coworker on the next till is looking really puzzled. Our tills tell us exactly how much change to give. I walk over and see that the till says to give eighty-five cents in change, and [Coworker] has three quarters in her hand.

Coworker: “How do I get to eighty-five cents?!”

She was completely stumped. She’s also an honors student.