what is the probability of getting atleast 50 heads while tossing 99 coins?

• (99c50+99c51+99c52.....99c99)(1/2)^99
• 11 years agoHelpfull: Yes(20) No(2)
• here is a case of binomial distribution...
  we want 50 heads from 99 coins
  so 99C50*(1/2)^50*(1/2)^49
• 11 years agoHelpfull: Yes(6) No(2)
• it is may be the question of binominalso theanswer may be 99c 55*(1/2)^50 *(1-1/2)^49
• 11 years agoHelpfull: Yes(4) No(5)
• required probability :
  (99c50 + 99c51 + ......... + 99c99)/(2^99)
  
  99c50 + 99c51 + ......... + 99c99=99c0 + 99c1 + ........ +99c49
  
  99c0 + 99c1 + ..... + 99c99 = 2^99
  
  2(99c50 + 99c51 + ......... + 99c99)/(2^100)
  
  2^99/2^100=1/2
  
  solution is 1/2
• 9 years agoHelpfull: Yes(3) No(1)
• as its asked to find probability of getting at least 50 head thus
  (99c50*(1/2)^50*(1/2)^49)+(99c51*(1/2)^50*(1/2)^49)+(99c52*(1/2)^50*(1/2)^49)+.......=(1/2)^99[99c50 +99c51+....] is same as = (1/2)^99[99c0 +99c1+......] = (1/2)^99[2^99] and hence =1
• 11 years agoHelpfull: Yes(2) No(7)
• what is the exact answer and also give proper solutions with full explanations.
• 11 years agoHelpfull: Yes(2) No(1)
• @INDRANIL BANERJEE i m not sure, but i thik this way only we can cover all the cases.
• 11 years agoHelpfull: Yes(1) No(1)
• at least means 50 or more than 50
  (1/2)^50*(1/2)^49+(1/2)^51*(1/2)^48+.......(1/2)^99
  there is 50 terms so 50*(1/2)^99 is the ans
  
• 11 years agoHelpfull: Yes(1) No(1)
• the required probability is 50/99
• 11 years agoHelpfull: Yes(0) No(11)
• (99!/(50!*49!))/2^99
• 11 years agoHelpfull: Yes(0) No(5)
• answer is 99c16*(0.5)^50*(1-0.5)^49
• 11 years agoHelpfull: Yes(0) No(4)
• I THINK KRATIKA IS RIGHT.....ARE U SURE @kratika jain??
  
• 11 years agoHelpfull: Yes(0) No(4)
• sorry previusly i hd posted a wrong answer it is may be the question of binominalso theanswer may be 99c 50*(1/2)^50 *(1-1/2)^49
• 11 years agoHelpfull: Yes(0) No(1)
• 1/2................................
  
• 11 years agoHelpfull: Yes(0) No(3)
• Is there any shortcut to solve the problem ..
• 9 years agoHelpfull: Yes(0) No(1)
• As probability asked is of getting atleast 50 heads and not exactly 50 heads, the solution should be 49*((1/2)^99)
• 9 years agoHelpfull: Yes(0) No(0)