1. T

    Mendel crossing with colour blindness (Probability)

    Hello everyone, I cannot seem to grasp the idea of how I have to use probability in this problem: "In Oslo 18121 school children were tested for colour blindess. These are the results: Male: 8324 not colour-blind, 725 colour-blind. Female: ? not colour-blind, ? colour-blind. Determine the...
  2. M

    Colour coded sequence pattern

    I'm terrible at maths, but I'm usually OK at generating a formula to feed a calculator or put in code. But for some reason, this has stumped me. I'm not even sure its meant to be in this forum, if not, please move it. I have a colour coded sequence pattern, there are 12 colours, each colour is...
  3. S

    (Hardish) Combinatorics problem: how often are consecutive balls the same colour?

    Hi all, first post, and not entirely sure it belongs here, but the problem seems hard enough to me! I have a bag containing X red balls and Y blue balls. Balls are withdrawn one at a time until no balls remain. What is the expected number of times that two blue balls are withdrawn in a row...
  4. Dinkydoe

    Colour Number Graph

    Hey, I'm a little stuck on the following problem: Let x_1,\cdots x_{kl+1} be n different real numbers. Show there exists a decreasing subsequence with at least k+1 terms, or a increasing sequence of at least l+1 terms. With as hint: \chi(K_{lk+1})>lk Wich suggests that the result can be...
  5. F

    Determining the colour of the last ball in a bag

    There exists a bag with a white and b black balls. Balls are chosen by the following method: i) A ball is chosen at random and discarded. ii)A second ball is then chosen. If colour is different from that of the preceding ball, it is replaced in the bag and the process repeated from the...
  6. B

    Minimum number of marbles to have taken one of each colour.

    Q9: In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many will he have to take out of his pocket to ensure that he has taken out at least one of each color? A. 11 B. 7 C. 8 D. 9 how??
  7. V

    Colour of lather

    Friends pls help me with this question... Soaps are of different colours but all of them form lather with a white colour . what is the reason behind that????
  8. D

    possible colour choices

    I have a packet of M&M’s. M&M’s come in six possible colours: red, green, blue, orange, yellow and brown. How many M&M’s need to be in the packet so that I can be sure I have: (a) At least five M&M’s of one colour. (b) At least nine M&M’s of one colour. (c) At least five red M&M’s. Here are...
  9. T

    4 colour theorum test cases

    A newbie here, Bth advanced Maths and Forum, Can anyone point me to a resource that has test cases for difficult to colour planar graphs that make coloring with four colors difficult. I have an idea that may demonstrate a simple proof for this theorem, however I need to find hard examples to...
  10. S

    All horses are the same colour?

    What is wrong with the following “proof” that all horses are the same color? Let P(n) be the proposition that all the horses in a set of n horses are the same color. Clearly, P(1) is true. Now assume that P(n) is true, so that all the horses in any set of n horses are the same color. Consider...
  11. Sazza

    Soil pH colour meanings.

    The information below is used for the next three questions Indicator paper used to test the pH of some soils had these colours. pH Colour 1 Crimson 3 Pale red 5 Orange 7 Yellow 9 Pale green 10 Green 12 Turquoise 14 Blue I know when you are measuring liquid that yellow is for acid, but what...
  12. malaygoel

    Colour and size of balls

    Two boxes contain between them 65 balls of several different sizes. Each ball is white, black red or yellow. If you take any five balls of the same colour, at least two of them will be of the same size(radius). Prove that there are at least three balls which lie in the same box have the same...
  13. C

    Five Colour Map

    Hi, can anyone help me prove that my five-colour map I created is not actually a five-colour map? I am not aloud to figure it out myself so I thought that this forum would be great place to ask someone else. Here it is: