Counting Definition and 392 Threads

  1. E

    Prime number counting function with error O(x^e)

    i have discovered a formula for \pi(x^{a}) being Pi the prime number counting function in terms of a triple integral...but you wll say..this is already made what is this good for?..in fact if you knew \pi(x^{a}) with a total error O(x^d) by setting a=Ad and making A--->oo (infinite) the total...
  2. A

    How can you explore coin combinations without making change?

    This question seems easy, but I don't understand what it's mean with "without making change". Could someone help me? If you have 2 dollars, 2 quarter and 3 nickels: a) how many different sums can you pay without making change? b) Change the quarters into dimes and answer again...
  3. A

    Question of counting and probability

    Could someone help me with this question ? There are two locks on the door and the keys are among the six different ones you carry in your pocket. In a hurry you dropped one somewhere. a) What is the probability that you can still open the door ? b) What is the probability that the...
  4. A

    Question of counting and probability

    Could someone help me with this question ? There are two locks on the door and the keys are among the six different ones you carry in your pocket. In a hurry you dropped one somewhere. a) What is the probability that you can still open the door ? b) What is the probability that the...
  5. B

    MATLAB Counting 4 Couple Table Arrangements in MATLAB

    I tried to write a function that would count all possible combinations that 4 couples could sit at a table assuming no man can sit next to his wife or next to another man. and 1wife and 1 husband sit at fixed positions. my problem doesn't compile and it says i either have too many or too few...
  6. E

    Driving a Train: 100 Passengers and Counting

    hmmmmmmmmmmm consider u r driving a train. there is 100 passengers in the train. at first station 50 more get into the train. 2nd station 27 more come in. but at the third station 45 left the train. 4th station no one leave or enter... 5th station 37 ins and 49 out. what is the name of...
  7. M

    Counting Probability & Statistics Basics - 10 Coin Tosses

    I'm taking a crack at learning probability and statistics starting from the basics. Anyways here is the question. --- A fair coin is tossed 10 times and the sequence of scores recorded. How many sequences are there? How many sequences are there that contain exactly 3 heads? ---...
  8. S

    Function Counter: Counting # of Functions in a File - Tips & Ideas

    Hi everyone, I need to write a C code program to count the # of fuctions used in a certain file (function counter) Can you guys give me some hints/suggestions/ideas ? Thanks, Stan
  9. O

    Counting the elements of a set of sets

    I have encountered this set problem that seems simple enough at first glance, but I'm pretty ignorant about formal set theory and unsure of the rules. As I encountered it, this is how it was written: For any set S let P(S) denote all subsets of S. For example S={1,2} Then P(S)= {Ø, {1}...
  10. M

    Counting Strings: Quarks, Dimensions & Brian Greene's Book

    I'm obviously not going to ask how many strings there are in the universe. :wink: my question. To each quark how many strings are there? Just one unique one? Billions and Billions? Also does Brian Greene's book. "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for...
  11. S

    Would i use the fundamental counting principal or is this a permutation

    thare are 8 candidates for three student seats how many different ways can the seats be chosen? With the FCP I get 24 If it is a permutation I get 336 which is right and why? Thanks for the help
  12. wolram

    Kyoto-Clock/"The Kyoto Clock: Counting Down to Global Climate Action

    The kyoto Clock http://www.junkscience.com/
  13. S

    Combinations are just an application of the counting principle?

    Is it fair to say combinations are just an application of the counting principle? I already understand that permutations are just an application of fundamental principle and that combinations are just an application of permutations. If it's fair to say that combinations are in fact, just an...
  14. S

    Combinations & Counting: Is There a Proven Formula?

    Is it fair to say combinations are just an application of the counting principle? I already understand that permutations are just an application of fundamental principle and that combinations are just an application of permutations. If it's fair to say that combinations are in fact, just an...
  15. L

    Solving 5-Stone Counting Problem w/ Restrictions

    Hi, I wasn't sure how to approach this problem: You have 5 differently colored stones-red, orange, blue, green, purple. If the green stone cannot be placed at the front or the back of the sequence, how many possible arrangements can you make? I know that without the above restriction, the...
  16. E

    Calculating Combinations with Constraints

    You have 10 pink balls and 15 purple balls. How many distinguishable arrangements are possible if two pink balls cannot be next to each other? I know the answer is 8008 but I have no idea how to get this
  17. A

    How Many 3-Letter Arrangements of aabbcccdddd Are Possible?

    hi everyone... how many arrangements of this word "aabbcccdddd" is possible if we only use 3 of them? I know if we could use all of them it would just be 11!/(2!2!3!4!), but what if we only use 3? :confused: Thanks in advance
  18. F

    Counting Problem: Proving the Integer Property of ((n^2)!)!/(n!)^(n+1)

    show that \frac{ ((n^2)!)!}{(n!)^{n+1}} is an integer. i was thinking of saying that there are so many people who can be put on a committee, etc etc which would make an integer. i don't think this is real hard but nothing is really jumping out at me
  19. B

    Counting Shortest Paths in a Square Grid

    Is there a concise, easily calculable way to count the sum of all the paths from the lower left corner of a square of integer size to the upper right corner where you only move up or right in steps of 1 unit, PLUS all the partial paths? i.e. if you have a city with roads in a 10x10 grid (100...
  20. T

    How Many Subsets of a Set with Odd Elements Can Have Half or Fewer Elements?

    The question is... How many subsets of a (2n+1)-element set have n elements or less? To figure this out I started by using a workable example. Obviously n must be small to keep the total number of subsets small. So I started with n=1 and so there are 8 total subsets. And of course in...
  21. V

    Counting Feynman Diagrams with n Vertices

    Is there a systematical way to count all the possible feynman diagram with vertices less than or equal to n...
  22. T

    How Many Functions, Book Arrangements, and Distinct Digits Can Be Calculated?

    1) If X is an n-element set and Y is an m-element set, how many functions are there from X to Y? I am not sure but I worked on this for a while and I come up with there are m^n possible functions. 2) There are five distinct computer science books, three distinct mathematics books and...
  23. S

    Even Order Groups: Counting Elements of Order 2

    Prove: a group of even order must have an even number of elements of order 2
  24. M

    Fundamental Counting Principle Math problem

    OK I'm unclear about how to use FCP to solve this problem: The final score in a hockey game is 5-2. How many different scores are possible at the end of the second period? :confused:
  25. T

    Counting Unique 7-Digit Phone Numbers - No Repeats

    Problem details: I think if I pretend that N is also a number from 0-9, then there would be P(10, 7) numbers without repeats, but then that's too much and I'm not sure how I can subtract the number's that N is not supposed to have. The other way I was thinking is the last 6 numbers can be...
  26. R

    Relativity and the Counting Process

    I refer you to a proposal about the finiteness of the integers: http://paulandellen.com/essays/essay089.htm How could this be? Everyone has assumed that the integers are infinite, yet a proof can be give to illustrate otherwise. Firstly we will use the characters necessary for expression of...
  27. E

    How many ways can prizes be distributed among lottery finalists?

    Here are my problems: 1) Suppose seven school children (3 girls and 4 boys) are lined up to board a school bus. Find the number of ways they could line up if no two boys are together. This arrangement would be BGBGBGB. So if I consider each BG as a unit, then there are 4! arrangements. But...
  28. Q

    Counting Question: 110 Counts in 1 Min - Probability (.15)

    dear reader, here is a quick counting question: A counter near a long-lived radioactive source measures an average of 100 counts per minute. The probabilty that more than 110 counts will be recorded in a given one-minute interval is most nearly (A) zero (B) .001 (C) .025 (D) .15 (E) .5 I...
  29. Q

    How Do You Estimate the Standard Deviation of a Radioactive Counting Rate?

    Dear members, here is a gre problem that I couldn't know how to tackle, any effort will be greatly appreciated. An experimenter measures 9934 counts during one hour from a radioactive sample. From this number the counting rate of the sample can be estimated with a standard deviation of most...
  30. S

    Counting Towers: Finding a Recurrence Relation

    A set of blocks contains blocks of heights 1, 2, and 4 inches. Imagine constructing towers of piling block of different heights directly on top of one another. Let t(n) be the number of ways to construct a tower of height n inches. Find a recurrence relation for t(1), t(2), t(3)... Here's...
  31. S

    Counting Theory and Addition Rule Confuses Me

    How many 16-bit strings contain exactly nine 1's? I said the total number is 2 to the 16th power, so to get half with 1's would be 2 to the 8th, or 256. How many 16-bit strings contain at least fourteen 1's? I have no idea. When determining a how to get 2 pair in a poker hand, why is...
  32. S

    Discrete Math - Counting Theory

    Hexadecimal numbers are made using the sixteen digits 0 - 9, A-F. how many hexadecimal numbers are there between the hexadecimal numbers 30 and AF? There are 8 numbers between 3 and A, so I got 3 x 16, but I don't really know.
  33. R

    Probability Question that involves alot of counting

    I can't seem to put the Fundamentals of Counting to good use... I have such a hard time answering probability questions with the rules of counting. Here's one question that blew my mind: There are 4 persons. The sample space E consists of the events E={E1, E2, E3, E4, E5 }. Let E1 be the...
  34. F

    Counting with 4 4s: From 0 to Infinity

    Here's an old one: starting with 0 (or 1) list all the natural numbers using nothing but 4 4s. I'll go first. 0 = (4 - 4)/(4*4) 1 = (4*4)/(4*4) 2 = (4*4)/(4*sqrt(4)) ... etc
  35. P

    Counting Methods: Understanding 8-Bit String Patterns

    The question is how many 8-bit strings have either the second or the fourth bit 1 (or both)? I know the soulution is 3*2^6 but why?? Also this question how many 8 bit strings begin and end with 1? is it 8C2?
  36. C

    Counting Relatively Prime Integers <500

    Having a lot of trouble with this problem as well: How many integers less than 500 are relatively prime to 500? I know that when two numbers are relatively prime, that means that the greatest common divisor of those two numbers is 1. But I can't figure out a formula that uses sets in order...
  37. C

    Counting Principles in Math: A Standard Deck of 52 Cards

    I have some questions about counting principles in mathematics: If I had standard deck of 52 playing cards, then a. How many ways can one draw a heart or a spade? b. " " an ace or a king? c. " " a card numbered 2 through 10? d. " " a card numbered 2 through 10 or a king? I got these answers...
  38. gimpy

    Distributing 5 Objects to 3 Boxes: C(5,3)

    I think i got this answer. How many ways are there to distribute five distinguishable objects into three indistinguishable boxes? Wouldn't the answer just be C(5,3) because the boxes are indistinguishable? Or do i treat this question the same as if the boxes were distinguishable?
  39. D

    How Does Two-Digit Counting Work Across Different Number Bases?

    A general two digit counting number is: d1*b + d0 = C ; where C is the count Let b = 2 as an example d 1 0 C ------ 0 0 0 0 1 1 1 0 2 1 1 3 b is the count of symbols in the digit, but it can start at 0 d1*0 + d0 = C ; works fine d0 = C ; and can be any base. d 1 0 C...
  40. P

    Fundamental Counting Principle problem

    The dial on a 3 number combination lock contains markings to represent the numbers from 0 to 59. How many combinations are possible if the first and second numbers differ by 3? What I did was: 1st number: It can be any of the 60 numbers (if we take 0 also as a #) 2nd number: I think since...
  41. M

    Counting Methods: Easier Ways to Solve Problems

    is there an easier way of knowing how to count certain sequences in a problem using the same concept, i mean there are formulas but how do we tell which one we should use.
  42. A

    What Makes the Number 9 So Mysterious and Fascinating?

    Hello all! First of all, please excuse me for barging in on you all like this. I am a nobody with little formal education in ANY field and I apologize if I seem a little mad. The bottom line is this - I just CANNOT find any satisfactory answers to my questions across the whole of the net and...
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