Brain Teasers
Macy Reject
A man was shopping at Macy's one very beautiful day. He bought a very expensive perfume for his wife and paid with a $100 bill. The cashier put a pen to the bill, made a black mark, then told the man that the bill was invalid. How did the cashier know the bill was fake?
Answer
The pen was a counterfeit detector that most cashiers have. It contains Lugols solution in it that turns dark purple/black when it comes in contact with starch. All paper has starch in it, except the paper that US paper bills are made out of (to prevent counterfeiting).Hide Answer Show Answer
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