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View Full Version : Probability Quiz II

HesseJam
12-23-2004, 07:53 AM
You receive an invitation to your High School Reunion. The Invitation went to all who were born in 1960. You talk about it to your school friend. You both know that about 180 guys in your school were born in 1960. Your friend proposes to you the following bet: You will not be able to find two guys on the reunion that have the exact same birthday. If he wins, he will get \$100, if you win you will get \$100. You both have no information on the birth dates.
You organized the last reunion 10 years ago and based on that experience you estimate that only about 40 people will actually show up. Should you take the gamble? At what odds?

niin
12-23-2004, 08:29 AM
Absolutely, take the bet. You only need about 23 people for this to be a better than even money bet. At 40 people, you'll have nearly a 90% chance to win.

HesseJam
12-23-2004, 09:15 AM
Correct. I see you guys are good!

Paul2432
12-23-2004, 12:38 PM
This assumes that the same number of people will attend the 20 year reunion as did the 10 year. It also assumes that if two people do indeed have the same birthday you will be able to find them.

I wouldn't take the bet because I would want to have a good time at the reunion, not go around bothering people asking them when their birthday was.

Paul

MortalWombatDotCom
12-23-2004, 08:09 PM
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Correct. I see you guys are good!

[/ QUOTE ]

that, or you are really easily impressed. here's one for you... you ask a set of reasonably intelligent people, many of whom have at least a passing interest in probability, a probability question that is used in the majority of texts which cover probability. how small a set do you need to pick to make the odds that nobody in that set has seen the question before nor is capable of working out the answer no worse than 1000 to 1 against?

mannika
12-24-2004, 01:27 AM
[ QUOTE ]
[ QUOTE ]
Correct. I see you guys are good!

[/ QUOTE ]

that, or you are really easily impressed. here's one for you... you ask a set of reasonably intelligent people, many of whom have at least a passing interest in probability, a probability question that is used in the majority of texts which cover probability. how small a set do you need to pick to make the odds that nobody in that set has seen the question before nor is capable of working out the answer no worse than 1000 to 1 against?

[/ QUOTE ]

ZING!
(Good one.)

niin
12-24-2004, 04:55 AM
Say you have 3 doors ...

SpaceAce
12-24-2004, 07:31 AM
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Say you have 3 doors ...

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Is there a prize behind one of them?

SpaceAce

HesseJam
12-25-2004, 03:16 AM
[ QUOTE ]
[ QUOTE ]
Correct. I see you guys are good!

[/ QUOTE ]

that, or you are really easily impressed. here's one for you... you ask a set of reasonably intelligent people, many of whom have at least a passing interest in probability, a probability question that is used in the majority of texts which cover probability. how small a set do you need to pick to make the odds that nobody in that set has seen the question before nor is capable of working out the answer no worse than 1000 to 1 against?

[/ QUOTE ]

LOL, yeah, yeah. /images/graemlins/blush.gif