Probability - Melody

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

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

23) 7 digit numbers with conditions

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

24) Combinations - vertices of a octahedron

http://web2.0calc.com/questions/two-of-the-vertices-of-a-regular-octahedron-are-to-be-chosen-at-random-what-is-the-probability-that-they-will-be-the-endpoints-of-an-edge-o

25) combination probabiliy - Not too difficult.

http://web2.0calc.com/questions/four-prime-numbers-are-randomly-selected-without-replacement-from-the-first-ten-prime-numbers-what-is-the-probability-that-the-sum-of-the-f

26) Lotto Probability

http://web2.0calc.com/questions/1-nbsp-in-the-smallstate-lottery-three-white-b***s-are-drawn-at-random-from-twenty-b***s-numbered-1-through-20-and-a-blue-superball-is

27) Playing cards probabilities

http://web2.0calc.com/questions/in-the-card-game-bridge-each-of-4-players-is-dealt-a-hand-of-13-of-the-52-cards-what-is-the-probability-that-each-player-receives-exactly

28) b***s - middle high level

http://web2.0calc.com/questions/there-are-four-red-b***s-and-two-white-b***s-in-a-jar-one-ball-is-randomly-removed-and-replaced-with-a-ball-of-the-opposite-color-the-jar

29) coin flipping

I made an intereresting discovery here.:)

http://web2.0calc.com/questions/a-large-regular-hexagon-is-drawn-on-the-ground-and-a-man-stands-at-one-of-the-vertices-the-man-flips-a-coin-if-the-coin-lands-heads-he

30) cards

http://web2.0calc.com/questions/carson-flips-over-the-cards-of-a-standard-52-card-deck-one-at-a-time-what-is-the-probability-that-he-flips-over-the-ace-of-spades-before-an

31) Number Theory - New to me. :/

http://web2.0calc.com/questions/a-point-is-on-a-number-line-but-it-is-limited-to-being-at-0-1-or-2-at-each-step-the-point-moves-1-unit-left-or-right-if-the-point-is-a

32) Expected values and probabilities

http://web2.0calc.com/questions/1-nbsp-two-numbers-x-and-y-are-randomly-chosen-from-the-interval-0-1-what-is-the-expected-value-of-x-y

33) Areas inside a square - great logic from Chris

http://web2.0calc.com/questions/1-nbsp-point-p-is-chosen-inside-square-abcd-what-is-the-probability-that-triangle-abp-has-a-greater-area-than-triangle-cdp

34) nonogon probability

http://web2.0calc.com/questions/a-a-regular-nonagon-9-sided-polygon-is-inscribed-in-a-circle-as-shown-below-three-of-the-9-vertices-are-selected-at-random-and-the-tri

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

http://web2.0calc.com/questions/1-nbsp-suppose-we-have-a-bag-with-8-slips-of-paper-in-it-six-of-these-have-a-1-on-them-and-the-other-two-have-a-3-on-them-what-is-the-ex

37) Expected values

http://web2.0calc.com/questions/1-nbsp-two-numbers-x-and-y-are-randomly-chosen-from-the-interval-0-1-what-is-the-expected-value-of-x-y

38) Treasue hunt:

http://web2.0calc.com/questions/a-pirate-is-searching-for-buried-treasure-on-6-islands-on-each-island-there-is-a-frac-1-4-chance-that-the-island-has-buried-treasure

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

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

40) Train probability

http://web2.0calc.com/questions/alex-needs-to-catch-a-train-the-train-arrives-randomly-some-time-between-1-00-and-2-00-waits-for-10-minutes-and-then-leaves-if-alex-also

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

http://web2.0calc.com/questions/two-numbers-between-0-and-1-on-a-number-line-are-to-be-chosen-at-random-what-is-the-probability-that-the-second-number-chosen-will-exce

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

http://web2.0calc.com/questions/in-triangle-abc-ab-5-bc-4-and-ca-3-point-p-is-randomly-selected-inside-triangle-abc-what-is-the-probability-that-p

43 ) Expected value

http://web2.0calc.com/questions/an-unfair-coin-lands-on-heads-with-probability-frac35-on-tails-with-probability-frac15-and-on-its-edge-with-probability-frac15-i

44) lights and colours

http://web2.0calc.com/questions/a-point-is-chosen-at-random-on-the-number-line-between-0-and-1-and-the-point-is-colored-green-then-another-point-is-chosen-at-random-on-t

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

http://web2.0calc.com/questions/in-how-many-ways-can-we-distribute-13-pieces-of-identical-candy-to-5-kids-if-the-two-youngest-kids-are-twins-and-insist-on-receiving-an-equ

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

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

http://web2.0calc.com/questions/1-nbsp-4-students-are-running-for-club-president-in-a-club-with-50-members-how-many-different-vote-counts-are-possible-if-all-50-members

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

http://web2.0calc.com/questions/we-have-8-pieces-of-strawberry-candy-and-7-pieces-of-pineapple-candy-in-how-many-ways-can-we-distribute-this-candy-to-4-kids#rr2

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)

http://web2.0calc.com/questions/a-and-b-take-turns-rolling-a-die-a-starts-the-winner-is-the-first-one-that-rolls-a-6-what-is-the-probability-that-a-wins

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

http://web2.0calc.com/questions/a-bag-contains-some-marbles-each-of-which-is-one-of-four-colors-red-white-blue-and-green-at-least-one-of-the-marbles-is-red-the-comp

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

http://web2.0calc.com/questions/my-basketball-team-has-eight-games-next-month-we-re-pretty-good-we-have-a-2-3-chance-to-win-in-each-game-what-is-the-probability-we-have

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

http://web2.0calc.com/questions/i-have-a-bag-with-5-pennies-and-3-nickels-i-draw-coins-out-one-at-a-time-at-random-what-is-the-probability-that-i-haven-t-removed-all-3-ni

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

http://web2.0calc.com/questions/how-many-20-digit-numbers-are-such-that-the-sum-of-their-digits-is-even

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