Math question

[wanksta]

I'm trying to settle a point with my friend. I'll skip all tge details. I'm sure I'm in the right place to find someone who can help me out here. Thanks in advance.
Question:
what are the odds of picking 3 numbers in any order out of 20?
Say a friend of mine is thinking of 6,7, and 18. What are the odds I guess all three the first time?
Off yalls subject I know but I know some of you guys are a math wizzards.

[jamesbettor]

1/20 x 1/19 x 1/18

=0.000146 or 0.0146%

[FourLengthsClear]

3/20
multiplied by
2/19
multiipled by
1/18

= 1 in 1140

[specialronnie29]

3/20
multiplied by
2/19
multiipled by
1/18

= 1 in 1140

[Richards]

And just to clarify for the OP, what makes FourLengthsClear correct over jamesbettor is the "in any order" clause. jamesbettors answer would be correct if the numbers needed to be selected in the correct order.

[specialronnie29]

And just to clarify for the OP, what makes FourLengthsClear correct over jamesbettor is the "in any order" clause. jamesbettors answer would be correct if the numbers needed to be selected in the correct order.

you answered your own q

[jamesbettor]

Sorry, I misread the question earlier.

[gohabsgo]

20!
_______ = 2280
3!(20-3)!

http://en.wikipedia.org/wiki/Lottery_mathematics

[specialronnie29]

= 1140

you just miscalculated the factorial

[benjy]

1140 is correct if your question is for lottery balls or similar where numbers can't be duplicated (e.g. 7, 14, 14).