XtremePapers

1/365 ,unless u consider that any 2 random persons u choose wud have a birthday on a certain date like 15 dec 24 feb,any 1 date gthen tht wud be 1/365^2 ...Nabeel kuch seekh ly Zain say

Dark Destination

1/365^2. That is what i am saying.

Am i wrong, M.Omar?

The probability of Person A having a birthday on for example, 4th October is 1/365.
The probability of Person B having birthday on 4th October is 1/365.

Thus, Probability of Person A AND Person B BOTH having birthday on the same day, is 1/365 * 1/365 = 1/365^2 = 1/133352..

M.Omar

Yeah then that,s correct

Dark Destination

Okay lol. Victory for the second time this day. :O

M.Omar

Not on the same day i mean on a specific date like if u specify on 15 oct for both then it,s 1/365^2 otherwise for same birthday dates then it,s 1/365

Dark Destination

You are making no sense, M dot omar, further maths master.

M.Omar

i mean for 2 persons, one can be born on any day right so the prob of 2nd sharing the same day is ofcourse 1/365 otherwise if we were to say tht the 2 persons be born on specified date like 15 oct then the prob of 1st being born on 15 oct is 1/365 and so is the second,s and THIS wud give 1/365^2

Dark Destination

Yes, so the probability of two people being born on the same day is 1/365^2

M.Omar

No..U know wht just google it

MarcoReus

When you see it.
http://i58.tinypic.com/dzusyb.png

K

Kamihus

Basically, two random people having same birth date is 1/365 but if you say that it should be on a specific date then its 1/365^2. You know your birth date, so the other person being born on that day is 1/365. But if you pick any two random people and say they are born on a specific date e.g. 1 Jan then its 1/365^2.

Dark Destination

But even if we know our own birthday, from a third persons perspective the probability of two people having the same birthday would be 1/365^2.

So generally talking, in this universe, two people sharing a birthday. That is the probability. We never take probabilities from our perspective.

K

Kamihus

Not really, it could be on any day. The two people could be born on any same day, 1 Jan or 8th Nov or any other date. So the probability would be 365/365^2 or 1/365 after simplification. But if you say that they should be both born on 8th Nov then its 1/365^2.

Dark Destination

Well, that is the case here i guess

MarcoReus

366*

Dark Destination

You still stuck on that. 365 days in a year. -.-

MarcoReus

There is the possibility that the guy was born on 29th February, the 366th day of a year.

Dark Destination

OMG. This is all so confusing. >.<
The probability that we calculated didn't include the leap year!

MarcoReus

Disaster. Blaphmesy. 2012. 1 mark gone on Maths P2. Extinction of the world. Ebola.

Man, this error trumps all of that.

M.Omar

Haha^

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