This will be my probability thread

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

1) Permutation Question

2) A selection problems

http://web2.0calc.com/questions/probability_29

3) Not very hard

4) What is the probabiliy that a rook (castle) and a bishop will threaten each other on a chess board ?

5) Poker

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

6,7) kids in a circle

8) distinct paths from one corner of a square to the other. :/

9) B***s in boxes

10) lollies and lunchboxes

http://web2.0calc.com/questions/i-really-need-help-please-i-have-no-idea-how-to-do-it-sorry

11) Using poisson distribution.

12) counting chord cuts in a circle

13) Probability - coloured cards

http://web2.0calc.com/questions/probability-of-a-deck-of-red-and-blue-cards

14) counting steps in a grid - :)

15) Car number plates with a twist problem

16) Cars in a carpark

17) b***s in a box

18) Cards

19) I am not sure what this is, some kind of probability. :/

20) Statistics with zscore BUT Binomial Distribution.

21) **How many ways can you pair an even number of people off. ** And other scenarios too.

22) How many ways can N peripherals be attached to k computers if every peripheral must be attached to exactly one computer and and every computer must be attached to at least one periferal.

So ther must be at least as many computers as peripherals $$k\ge N$$

I believe that this is the formula that Nauseated presented us with

$$\displaystyle \sum \limits_{i=0}^{\textcolor[rgb]{1,0,0}{N-1}} *(-1)^i*\binom{N}{i}* (N-i)^k$$

http://web2.0calc.com/questions/this-is-question-from-assignment-book

23) 7 digit numbers with conditions

http://web2.0calc.com/questions/please-explain-thoroughly

24) Combinations - vertices of a octahedron

25) combination probabiliy - Not too difficult.

26) Lotto Probability

27) Playing cards probabilities

28) b***s - middle high level

29) coin flipping

I made an intereresting discovery here.:)

30) cards

31) Number Theory - New to me. :/

32) Expected values and probabilities

33) Areas inside a square - great logic from Chris

34) nonogon probability

35) Expected values

http://web2.0calc.com/questions/consider-a-random-variable-x-such-that-p-x-1-p-x-1-frac12

36) Expected values

37) Expected values

38) Treasue hunt:

39) Pascal Triangle questions (A few around this page)

http://web2.0calc.com/questions/page/1663

40) Train probability

41) Probability on a number line (26/4/15 Mellie)

42) Another geometry special (29/4/15 Mellie)

43 ) Expected value

44) lights and colours

45) Children and lollies and did I just discover a formula :/

46) **How many ways can 15 Identical candybars be distributed to 5 different children **

** (15+5-1) C 15 ways (I think)**

**Learning sites for these lollie questions**

http://en.wikipedia.org/wiki/Stars_and_bars_(combinatorics)

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

47) Another lollie question from Mellie

48) **LEFT FACTORIAL**

The subfactorial or **left factorial**, written, is the number of ways that *n* objects can be arranged where no object appears in its natural position (known as "derangements.")

http://web2.0calc.com/questions/what-does-the-meaan#r3

49) A and B alternate to roll a die. What is the prob that A rolls a 6 first. (15/5/15)

50) Minimum number of marbles needed (from Mellie) (15/5/15)

51) Chance of 4 winning games in a row in basketball (from Mellie) (15/5/15)

52) Nickels and Pennies (from Mellie) (15/5/15)

53) How many 20 digit numbers are even (from Mellie) (15/5/15)

54) What is the chance of makinga cyclic quad ? (from Mellie) (15/5/15) (page 1769)

**Repeating probablility problem**

http://web2.0calc.com/questions/monty-hall-problem

**Probability question.**

**Very tricky selections question. (Alan and Bertie 4/3/15)**

http://web2.0calc.com/questions/please-explain-very-well-in-this-question_3

**Poker probabilities** (added 22/3/15)

**squares permutations** (added 22/3/15)

**More squares permutations** (added 22/3/15)

**Probability - new formula from Nauseated.**

http://web2.0calc.com/questions/how-many-ways-can-3-identical-b***s-go-into-9-unique-boxes

http://web2.0calc.com/questions/this-is-a-continuation-of-an-earlier-counting-question-that-nauseated-and-geno-answered

**Probability - counting**

http://web2.0calc.com/questions/i-really-need-help-please-i-have-no-idea-how-to-do-it-sorry

**Probability - counting**

http://web2.0calc.com/questions/this-is-question-from-assignment-book

**An alternative diagram method** from Alan - This is really neat

http://web2.0calc.com/questions/i-think-this-is-a-mutually-exclusive-question

Melody Feb 1, 2015