A drawer holds 4 red hats & 4 blue hats.What is the P(A) of getting exactly three blue hats when taking out 4 red hats randomly out of drawer & immediately returning every red hat to the drawer before taking out next?

• possible outcomes=
  (RRRR)(RRRB)(RRBR)(RBRR)(BRRR)(BBBR)(BBRB)(BRBB)(RBBB)(RRBB)(BBRR)(RBBR)(BRRB)(RBRB)(BRBR)(BBBB)
  
  so total 16
  n we want exactly 3 blue hats
  so 4/16=1/4 ans.
  
• 10 years agoHelpfull: Yes(24) No(5)
• 1/2
  4 ways to have 3 blue hats (BBBR, BBRB, BRBB, RBBB)
  
  4 ways to have 3 red hats (RRRB, RRBR, RBRR, BRRR)
  Total number of possibilities : 2*2*2*2 = 16
  8/16=1/2
• 10 years agoHelpfull: Yes(4) No(4)
• 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
  
• 10 years agoHelpfull: Yes(1) No(0)
• Ans: 1/16 (4/8*4/8*4/8*4/8)
• 8 years agoHelpfull: Yes(0) No(0)