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probability

by earth@work » Wed Oct 08, 2008 5:01 pm
In a lottery, a person choses six different natural numbers at random from 1 to 20, and if these six numbers match with the six numbers already fixed by the lottery committee, he wins the prize. What is the probability of Winning the prize in the game.
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by earth@work » Thu Oct 09, 2008 9:53 am
pls help.... answer is 1/38760
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by mental » Thu Oct 09, 2008 10:14 am
just think it slighly different manner

how many ways can 6 numbers be chosen out of 20 numbers

they are not asking arrangements

20c6 = 20!/14!*6! = solve it you get 38760

one combination is selected out of it by selectors

probability = 1/38760
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by earth@work » Thu Oct 09, 2008 10:30 am
thanks a lot!
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by 4meonly » Sat Oct 11, 2008 12:32 am
I doubt whether this Q is correct

4me, the probability will be

1/20 * 1/19 * 1/18 * 1/17 * 1/16 * 1/15 we'll get less then 1/38760

Because 123456 is not the same as 654321

answer 1/38760 assumens that order is not important but it should be important!!!
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Re: probability

by mental » Sat Oct 11, 2008 7:41 am
earth@work wrote:In a lottery, a person choses six different natural numbers at random from 1 to 20, and if these six numbers match with the six numbers already fixed by the lottery committee, he wins the prize. What is the probability of Winning the prize in the game.
the quaestion is not talking about arrangements

also just think that it has double digit numbers
20, 19, 8, 7 are actually only four numbers, but if we write in one go....201987...can also mean...2,0,1,9,8,7...6 different numbers!!!!

neways thats im-material
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by canuckclint » Sat Oct 11, 2008 9:25 am
4meonly wrote:I doubt whether this Q is correct

4me, the probability will be

1/20 * 1/19 * 1/18 * 1/17 * 1/16 * 1/15 we'll get less then 1/38760

Because 123456 is not the same as 654321

answer 1/38760 assumens that order is not important but it should be important!!!
This does take into account order. Since the first number is 1/20 chance and so on.
Its just the probability happens to be the same if they are switched.
For example. what is the probability of coin toss:
TTH or HTT are the same 1/8

Makes sense?
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by hgupta0 » Tue Dec 30, 2008 4:57 pm
I think the problem with the question is that it does not specify anything about order. Re-reading the question again it seems the condition for winning is that 6 numbers match with the numbers defined by the committee. Hence order does not matter
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4meonly wrote:I doubt whether this Q is correct

4me, the probability will be

1/20 * 1/19 * 1/18 * 1/17 * 1/16 * 1/15 we'll get less then 1/38760

Because 123456 is not the same as 654321

answer 1/38760 assumens that order is not important but it should be important!!!
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by vittalgmat » Wed Dec 31, 2008 4:41 am
well the Q is ambigous.

If all the 6 numbers are considered together as 6digit number then it is permutations

If the 6 numbers are considered as 6 individual numbers then,
it is combination.

HT helps
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