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Birthday Paradox & Zodiac Signs
Marie's party was an evident success. A few dozens of guests sitting around four tables shared the joy and good humour of the celebration, while savouring the tasty food and refreshing drinks provided by the hostess.
At her table, Anne looked at each one with a quirky smile and said I bet that there is an 80% probability that two of us at this table have the same zodiac sign!The others looked at her incredulously: How could she ever know?
She noticed the scepticism and took the challenge a bit farther. Glancing around the room, she pronounced calmly ...and I reckon that there is a 95% probability that two persons in this room share the same birthday!
Anne has got a reputation for having a sharp mind. For her to feel confident in stating such probability values, how many people do you figure were sitting at her table, and how many guests were there in the room altogether?
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Updated: 04/28/2017 16:04:00