Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Probability: coin toss

  1. Mar 4, 2010 #1
    Pravesh and Solly usually go to a coffee shop during their lunch break and toss a coin to see who will pay. The probability that Prevesh will pay three days in a row is

    (1) 0.025
    (2) 0.500
    (3) 0.125
    (4) 0.015

    My attempt (I am not sure if this is right)

    X= number of days that Prevesh will pay

    x- P(x)
    0 - 0.250
    1 - 0.250
    2 - 0.250
    3 - 0.250

    So I assume that the correct answer is (1)?
     
  2. jcsd
  3. Mar 4, 2010 #2
    i think since pravesh would have 1/2 chance of paying for a lunch on one day, you would have to multiply that by 3 and the odds become less for him to pay 3 times in a row therefore you would get 1/8 from 1/2 * 1/2 *1/2. Getting 0.125
     
  4. Mar 4, 2010 #3
    Thank you
     
  5. Mar 4, 2010 #4

    berkeman

    User Avatar

    Staff: Mentor

    Please do not do the OP's homework for him. It is cheating, and not allowed here at the PF.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook