a drawer hold 4 red hates and 4 blue hates. what is the probability of getting exactly 3 hatesv when taking out 4 hates randomly out of the drawerband imediately returining every hate to the drawer before taking out the next?

• As the objects are replaced, the probability of drawing red or blue is equal.
  Probability to draw exactly 3 red hats and 1 blue hat =1/2*1/2*1/2*1/2=1/16
  Similarly probability to draw exactly 3 blue hats and 1 red hat =1/2*1/2*1/2*1/2=1/16
  Total probability =1/16+1/16=1/8
• 8 years agoHelpfull: Yes(18) No(2)
• One way to look at this problem is to count all the possible outcomes of 3 red plus 3 blue and dividing it by the total number of all color combinations
  RRRB BBBR
  RRBR BBRB
  RBRR BRBB
  BRRR RBBB which is a total of 8
  For all possible color combinations, there are these (8) plus all red and all blue (2), two of each color (6) making a total of 16. The probability of getting 3 red or 3 blue is therefore 8/16 = 1/2
• 8 years agoHelpfull: Yes(3) No(9)
• Probablity of taking out a particular color hat = 4/8 = 1/2
  
  P(BBBR) = (1/2)^4
  P(BBRB) = (1/2)^4
  P(BRBB) = (1/2)^4
  P(RBBB) = (1/2)^4
  total = 4 * (1/2)^4
  
  similary for (RRRB) = 4 * (1/2)4
  
  answer = 8 * (1/2) ^4 = 1/2
• 8 years agoHelpfull: Yes(0) No(0)