TEMPORARY MODE ENABLED
New posts, edits, and any changes will not be saved during the transition period.
Registrations are temporarily disabled until the migration is complete.

  1. Devante

    OP Devante Crescent fresh at best.
    Member

    Joined:
    Nov 29, 2002
    Messages:
    1,221
    Country:
    United States
    Hey guys.

    Sounds dumb but how do I find the probability of the following question?

    A class has 32 students. Out of that class, 4 will fail.
    Rudy is in this class.
    What is the probability of Rudy failing?

    I keep coming up with 1/8 but I think I'm missing a step.
     
  2. Recorderdude

    Recorderdude Musician, Animator, Buffoon.
    Member

    Joined:
    Jun 19, 2010
    Messages:
    1,392
    Country:
    United States
    4/32

    divide both by four

    1/8

    it's that simple. 1/8 will fail and he has a 1/8 chance of failing. this could also be expressed as .125, 12.5% or 1:8.
     
  3. s4mid4re

    s4mid4re  
    Member

    Joined:
    Apr 2, 2011
    Messages:
    1,669
    Country:
    United States
    to be a little clearer, 1/8 = 1÷8
    if you solve 1÷8, it becomes .125 (you can also solve by 4÷32 and get the same answer)
    move the decimal 2 places to the right and you get the percentage (12.5%)
    1:8 (one to eight) is the simplified ratio form. just think of the colon as a division sign.
     
  4. Nathan Drake

    Nathan Drake Obligations fulfilled, now I depart.
    Member

    Joined:
    Jan 2, 2011
    Messages:
    6,192
    Country:
    I wanna say 1/256. There is a 4/32 chance that four of the students will fail. There is also a 1/32 chance that the student could be Rudy.

    To account for this, you have to set it up as follows:
    (4/32)(1/32) = 1/256 chance that the failed student is Ricky

    I wanna go ahead and say this is wrong though. I could say how to do this perfectly if I felt like pulling out my notes from my mini-probability unit in Pre-Calculus earlier this year. Instead of people, it was dice. It was something like the odds of it being a number 1 - 3 in six rolls, and how many times the number 2 would show up and crap like that.

    Take my answer with a grain of salt, or a shaker, or a factory full. [​IMG]
     
  5. s4mid4re

    s4mid4re  
    Member

    Joined:
    Apr 2, 2011
    Messages:
    1,669
    Country:
    United States
    I don't think that's what's being asked. If my interpretation is correct, this would be a variant of the question:
    One of the 4 students that are failing can be Rudy, out of a total of 32 students. What is the probability that Rudy is 1 of the 4 students?
     
  6. SinHarvest24

    SinHarvest24 Shiroyasha
    Member

    Joined:
    Oct 8, 2010
    Messages:
    997
    Country:
    Chad
    you were just over-thinking things ^

    The answer you got is correct. So is everyone else here.
     
  7. Devante

    OP Devante Crescent fresh at best.
    Member

    Joined:
    Nov 29, 2002
    Messages:
    1,221
    Country:
    United States
    Thanks guys. :>
     
  8. wasim

    wasim ♫ Music addict ♫
    Member

    Joined:
    Nov 13, 2010
    Messages:
    907
    Country:
    India
    looks like there are many maths genius here

    ( solution for my homeworks is here [​IMG] )
     
  9. CarbonX13

    CarbonX13 GBAtemp 台灣人
    Member

    Joined:
    Aug 27, 2010
    Messages:
    1,399
    Country:
    Taiwan
    Um... this really takes nothing more than what you learn in maybe grade 4 elementary school... [​IMG]
     
  10. wasim

    wasim ♫ Music addict ♫
    Member

    Joined:
    Nov 13, 2010
    Messages:
    907
    Country:
    India
    i learned this in 6th grade
     
  11. Chhotu uttam

    Chhotu uttam DOH HO HO HO
    Member

    Joined:
    Dec 6, 2010
    Messages:
    864
    Country:
    India
    but i learned it in 9th grade.(joking)
     
  12. Nathan Drake

    Nathan Drake Obligations fulfilled, now I depart.
    Member

    Joined:
    Jan 2, 2011
    Messages:
    6,192
    Country:
    I didn't start to learn how to add, subtract, multiply, and divide fractions until pre-algebra. Through elementary school, it was pretty much all basic shit and memorizing stuff you'll never need to memorize again.
     
  13. chris888222

    chris888222 GBAtemp's Flygon Fan
    Member

    Joined:
    Oct 11, 2010
    Messages:
    5,532
    Country:
    Senegal
    Darn my math sucks :/
     
  14. mcp2

    mcp2 GBAtemp Advanced Fan
    Member

    Joined:
    Jun 3, 2007
    Messages:
    578
    Country:
  15. SamAsh07

    SamAsh07 GBAtemp Addict
    Member

    Joined:
    Jan 27, 2009
    Messages:
    2,696
    Country:
    Bosnia and Herzegovina
    ^ You forgot to state - use magnets for faster calculation AND Math question writing teachers will go bankrupt.
     
  16. CarbonX13

    CarbonX13 GBAtemp 台灣人
    Member

    Joined:
    Aug 27, 2010
    Messages:
    1,399
    Country:
    Taiwan
    Maybe it's the States then. I learned how to divide, multiply, add, and subtract factions in grade 4, and BEDMAS and such by grade 5.
     
  17. Devante

    OP Devante Crescent fresh at best.
    Member

    Joined:
    Nov 29, 2002
    Messages:
    1,221
    Country:
    United States
    P.S. I was drunk when I made this thread. ;>
     
Draft saved Draft deleted
Loading...

Hide similar threads Similar threads with keywords - problem, simple, solve