text: # Simple probability question
  
  • Oct 5th 2010, 01:30 AM
  Stroodle
  Simple probability question
  Kim goes to the sports centre each evening and either works out in the gym or has a swim. She never has a swim two evenings in a row. If she has a work-out in the gym one evening, then the next evening she is twice as likely to have a swim as she is to have a work-out in the gym. On a particular Monday evening, she works out in the gym.
  
  What is the probability that she works out in the gym on both the Tuesday and Wednesday evenings of that week?
  
  I can see that Pr(swim|swim)=0, and that Pr(gym|swim)=1. Just can't get my head around how to get Pr(gym|gym) and Pr(swim|gym).
  
  • Oct 5th 2010, 02:12 AM
  downthesun01
  Since,"if she has a work-out in the gym one evening, then the next evening she is twice as likely to have a swim as she is to have a work-out in the gym."
  
  I would say that:
  
  pr(gym|gym)=1/3
  
  pr(swim|gym)=2/3
  
  Since the sum of the two probabilities must equal 1 because it's stated that she does some sort of work out every evening.
  Someone please correct me if I'm wrong.
  • Oct 5th 2010, 02:19 AM
  Stroodle
  Ahh, of course. That's the same answer as in my text :)
  
  Thanks heaps :)
metadata: {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0}