What's The Probability?
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24-02-2015, 12:42 PM (This post was last modified: 24-02-2015 01:00 PM by ScatteredThoughts.)
RE: What's The Probability?
I'm lazy and also suck at the maths, so I just searched a bit until I found this:

http://www.calctool.org/CALC/math/probability/birthdays

According to that tool, there is 100% chance that 2 people will have the same birthday.

**ETA**

And I see that I didn't fully read the initial post. I don't know how you would determine the chances of the people actually sitting next to each other. Interesting problem.
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24-02-2015, 12:48 PM
RE: What's The Probability?
(24-02-2015 08:09 AM)DLJ Wrote:  A look of surprise from the Chinese guy as he spotted that they shared the same birthday.

What's the chances?

At a guess, I'd say there were about 40 rows, with three seats per row each side of the aisle... maybe 240 seats about 90% occupied.
The chances of having someone sit right next to you who shares the same birthday is 1/365.
If you have a person to your right and one to your left then it is 2/365 which is 1/182.5

If he is on a return flight then we halve that again. 1/91.25

Then you have to consider how many flights the person takes and also consider if we are to include bus travel, train travel, sitting in a movie theatre etc.

I'd say it won't be long before you sit next to someone with the same birthday.
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24-02-2015, 05:24 PM
RE: What's The Probability?
Cool story, needs more dragons Tongue

Where you got these pics stored? If you can email them to me, I can upload for you. They'd be a nice touch to the story Big Grin

I hope that the world turns, and things get better. But what I hope most of all is that you understand what I mean when I tell you that, even though I do not know you, and even though I may never meet you, laugh with you, cry with you, or kiss you, I love you. With all my heart, I love you. - V for Vendetta
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24-02-2015, 06:34 PM
RE: What's The Probability?
(24-02-2015 05:24 PM)Smercury44 Wrote:  Cool story, needs more dragons Tongue

Where you got these pics stored? If you can email them to me, I can upload for you. They'd be a nice touch to the story Big Grin

On my iPhone. Can't seem to upload them to my newer laptop. I can email to myself but won't do that until I'm back in Singapore (roaming charges!!).

I'll try to remember to do it next week.

Thanks.

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24-02-2015, 07:32 PM
RE: What's The Probability?
Pretty sure it was aliens bro.

[Image: oscar.png]
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24-02-2015, 07:34 PM
RE: What's The Probability?
2-1 maybe 3-1tops.Tongue
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24-02-2015, 07:53 PM
RE: What's The Probability?
Had you bothered to ask you would have learned that everyone on that flight had the same birth day and month. Drinking Beverage

Happens all the time.

“I am quite sure now that often, very often, in matters concerning religion and politics a man’s reasoning powers are not above the monkey’s.”~Mark Twain
“Ocean: A body of water occupying about two-thirds of a world made for man - who has no gills.”~ Ambrose Bierce
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24-02-2015, 07:59 PM
RE: What's The Probability?
(24-02-2015 07:53 PM)Full Circle Wrote:  Had you bothered to ask you would have learned that everyone on that flight had the same birth day and month. Drinking Beverage

Happens all the time.

[Image: f_8321a8380c.jpg]

I hope that the world turns, and things get better. But what I hope most of all is that you understand what I mean when I tell you that, even though I do not know you, and even though I may never meet you, laugh with you, cry with you, or kiss you, I love you. With all my heart, I love you. - V for Vendetta
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24-02-2015, 08:36 PM (This post was last modified: 25-02-2015 02:36 PM by Full Circle.)
RE: What's The Probability?
Let’s see...7,200,000,000 on the planet divided by 365 = 19,726,027 people with your birthday

IATA members flew 1.6 billion pax, so adding in non-IATA members probably brings it up to 1.65 billion worldwide. It works out to 4.5 million per day.
http://www.airliners.net/aviation-forums...n/4108229/

4,500,000/7,200,000,000 = 0.000625 or 0.0625% passengers/day as a % of global population

19,726,027 x 0.0625% = 12,329 passengers with your birth date flying on any one day.

93,000 flights per day
http://www.flixxy.com/scheduled-airline-...ldwide.htm
(cool simulation btw)

12,329/93,000 = 0.13257 people with your birthday per flight

So a person with your birthday is flying on 13.3% of daily flights.

3 people with your birthday 13.3%/3 = 4.4% of flights EDIT #1: see below

Seating capacity of airliner? Say an Airbus 320a
[Image: CA_A320_1.gif]

There are 32 three seat possibilities.
If the three of you were the only 3 passengers with your birth date the chances of all three sitting on the same 3 seat row?

Of you seating in that row 1/32 = 0.03125
Of you and one other guy 1/32 X 1/32 = 0.009765625
Of all three on same row 1/32 X 1/32 X 1/32 = 0.00305175781

Odds of you three in same row 0.00305175781 X 0.044 (flights with 3 people with your birthday) = 0.00013427734 or 0.013% or 1.3 in 10,000

Someone needs to check my math.

EDIT #1: I think I made a mistake on this step: 3 people with your birthday 13.3%/3 = 4.4% of flights, should not have divided but instead multiplied as follows:

It should be 0.133 X 0.133 X 0.133 = 0.002197 or 0.22% of flights with three people with the same birthday.

So the last calculation would be 0.00305175781 X 0.002197 = 0.00000670471 or 0.00067% = 6.7 in 1,000,000 or

1,000,000/6.7 = 1 flight per 149,253

This looks correct. Chances are that it’ll never happen again TO YOU.

EDIT #2:
We know there are 93,000 flights per day...
149,253/93,000 = 1.6
This means that this happens once every day and a half - 3 passengers sitting next to each other with the same birth date!

Someone please double check my math.

“I am quite sure now that often, very often, in matters concerning religion and politics a man’s reasoning powers are not above the monkey’s.”~Mark Twain
“Ocean: A body of water occupying about two-thirds of a world made for man - who has no gills.”~ Ambrose Bierce
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24-02-2015, 08:50 PM
RE: What's The Probability?
(24-02-2015 07:59 PM)Smercury44 Wrote:  
(24-02-2015 07:53 PM)Full Circle Wrote:  Had you bothered to ask you would have learned that everyone on that flight had the same birth day and month. Drinking Beverage

Happens all the time.

[Image: f_8321a8380c.jpg]

Bill & Ted was on yesterday. Whoa. Cool
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