Roll a 6-sided die until you have rolled a total of 25 6's.

Hello,

I am trying to wrtie a script to roll randi(6) and loop until it has reached 25 sixes and then count how many rolls it took. Help please.

Answer 1

[KSSV]

count = 0 ;
iwant = zeros([],1) ; 
i = 0 ; 
while count ~= 25
  i = i+1 ; 
  N = randi(6) ;
 iwant(i) = N ;  
  if N == 6
    count = count+1 ; 
  end
end

Answer 2

[Asad (Mehrzad) Khoddam]

find(cumsum(randi(6,1,1000)==6)==25,1)

[Walter Roberson]

Though in theory there is a chance that you would not have reached 25 6's by 1000 rolls....

[Asad (Mehrzad) Khoddam]

Yes, you are right. Simply if it happens, you can try again

The probability is 1.536e-48 (it happens once in 6.5e47 tries)

[Walter Roberson]

You wouldn't quite just try again... you would have to subtract off the number of 6's that you got up to that point, and you would have to add the number of attempts you already made to the index.