Answer:
0.37
Step-by-step explanation:
To resolve the given problem we will apply
persistent time Markov chain : Â n = 0, 1, . . . , 4
 n = number of individuals pausing
where The equalization conditions are : πn = ( πn - 1/2 )
Given that  :
n = 0,1,2,3,4
π0 = 1/( 1 + 2−1 + 2−2 + 2−3 + 2−4) = 0.52 = 16/31
Also the normal number of travelers found by Ella will be represented as
E(N) = (π1 + 2π2 + 3π3) / ( π0 + π1 + π2 + π3) ------- ( 1 )
where : π1 = 8,  π2 = 4,  π3 = 2 , π0 = 16/31  input values into equation 1
E ( N ) = Â 22/30
given that the True to form hanging tight time = 0.5
hence Holding holding time = E(N ) * 0.5
therefore  the expected waiting time for Ella = ( 22/30 ) * 0.5 = 0.37