Today's Word Problem

A volleyball player stops at a fast food restaurant in Downers Grove to grab a bite to eat before his Thursday night game. The price of his meal totals $9.11. He checks the money in his pocket and doesn't have enough change but has a spare penny. He hands the cashier $20.01. The cashier fat fingers the tender amount and enters $10.01. The automated change machine returns $0.90 and the cashier immediately realizes she has made a mistake entering the amount tendered.

How many teenage cashiers does it take to realize another $10.00 in change is owed? Show your work.