say that we throw a coin fair coin n times we say that the s

say that we throw a coin fair coin n times. we say that the sequence is i-good if the value of i,i+1 and i+2 are all head?    

Solution

If a coin is tossed n times , no of possibilities for heads to come three times consecutively is n-2 (i.e. i ranges from 1 to n-2)

The probability of each toss to get head is 1/2

the sequence is i-good if the value of i,i+1 and i+2 are all head