What Are the Odds of Finding a Car License With Triple 9

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One of my classmates asked me what would be the odds of finding a car plate no with three comsequetive 9's on it.

This ISN'T A HOMEWORK QUESTION

Just a random thought.

So...if anyone is from different places of the earth with different car plate formats ,could you'll inform ?
 

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  • #2
PeroK
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One of my classmates asked me what would be the odds of finding a car plate no with three comsequetive 9's on it.

This ISN'T A HOMEWORK QUESTION

Just a random thought.

So...if anyone is from different places of the earth with different car plate formats ,could you'll inform ?
In the UK there are only two digits in the plate nowadays. But, there may be a few personalised plates or older plates.

The best answer is that you have to count the total number of cars on the road and count how many have 999 in the plate.
 
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In the UK there are only two digits in the plate nowadays. But, there may be a few personalised plates or older plates.

The best answer is that you have to count the total number of cars on the road and count how many have 999 in the plate.
Great.....

So ill take a total of 50 cars i see in one day...and then use basic probabilty formula

But i dont think my state will encompass the whole globe.

So im gonna have to ask a bunch of people from diff countries to do a similar observation and tell...right ?

Is there any other fancy shwancy way though ?
 
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PeroK
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Great.....

Is there any other method....i dunno some complex differntiation intervration or some cryptic formula or something ? I mean although i can get a perfect method by this answer....3 million cars are there in my state alone....let alone the world !
In the old days British cars had three (*) numbers and they were generally random from 1 to 999. So, the odds were, give or take, 1/999.

(*) I think they were up to three numbers, so you could have "6" or "31" or "522" etc.

But, then, the government started to hold back special numbers and sell these. And, then, they decided to have just two numbers.

So, now, without looking at the government's licensing database, I have no idea how many 999's there are on the British roads.

The only way you can use mathematical probability theory is if you know how licence numbers are distributed.
 
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In the old days British cars had three (*) numbers and they were generally random from 1 to 999. So, the odds were, give or take, 1/999.

(*) I think they were up to three numbers, so you could have "6" or "31" or "522" etc.

But, then, the government started to hold back special numbers and sell these. And, then, they decided to have just two numbers.

So, now, without looking at the government's licensing database, I have no idea how many 999's there are on the British roads.

The only way you can use mathematical probability theory is if you know how licence numbers are distributed.
Darn it ! And such info we lack....

Ps : 3 consequetive numbers are extremely common in india ! We have a four no. Number plate
 
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Probably 1/998 as maybe they were superstitious and took 666 out of the distribution
 
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Probably 1/998 as maybe they were superstitious and took 666 out of the distribution
Whoa ! Really ! Thats rather cool actually
 
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Okay guys...today i took down observations.

Out of 50 cars i saw on the road....0 had a triple 9 on the no. Plate.
I saw 2 with a double 9 and 12 had repeating numbers consequetvely but none had a triple 9.
 
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Ill try again tom.
 
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phinds
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I wouldn't be surprised if some states prohibited 666 and 999
 
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I wouldn't be surprised if some states prohibited 666 and 999
In india we dont consider it such a big deal,so im pretty sure there are cars out there !!! Finding them is the problem !
 
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One of my classmates asked me what would be the odds of finding a car plate no with three comsequetive 9's on it.

This ISN'T A HOMEWORK QUESTION

Just a random thought.

So...if anyone is from different places of the earth with different car plate formats ,could you'll inform ?
But I have seen license plates with wildly different formats: Letter Number Letter Letter.... etc. What format is your classmate referring to.
 
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  • #13
PeroK
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Okay guys...today i took down observations.

Out of 50 cars i saw on the road....0 had a triple 9 on the no. Plate.
I saw 2 with a double 9 and 12 had repeating numbers consequetvely but none had a triple 9.
If the licences are random 4-digit numbers (including 0), then the probability of having a double 9 somewhere is about 2.7%. That's about one in every 37 cars.

But, the probability of having a triple 9 is only about 0.2%. That's only one car in every 500.

The probability of having any double is about 24%; about one car in every 4.

Your data fits these calculations.
 
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If the licences are random 4-digit numbers (including 0), then the probability of having a double 9 somewhere is about 2.7%. That's about one in every 37 cars.

But, the probability of having a triple 9 is only about 0.2%. That's only one car in every 500.

The probability of having any double is about 24%; about one car in every 4.

Your data fits these calculations.
But I have seen license plates with wildly different formats: Letter Number Letter Letter.... etc. What format is your classmate referring to.
I dont think he knew that himself to be honest !!!!
But im sure he will be satisfied by PeroK 's answer because thats the format we use in India .


Anyway Thank you all for contributing in this thread and helping me !!! It was extremely kind of you'll.

Have a great day ahead.

If you'll have anything more to say please feel free to do so.
 
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