Question

We have two coins, a and

b. for each toss of coin a, the probability of getting head is 1/2 and for each toss of coin b, the probability of getting heads is 1/3. all tosses of the same coin are independent. we select a coin at random and toss it till we get a head. the probability of selecting coin a is ¼ and coin b is 3/4. what is the expected number of tosses to get the first heads

Answer 1

25..................