1 votes 1 votes Each day, you independently decide, with probability p, to flip a fair coin. Otherwise, you do nothing. (a) What is the probability of getting exactly 10 Heads in the first 20 days? (b) What is the probability of getting 10 Heads before 5 Tails? Probability gravner probability engineering-mathematics + – ajaysoni1924 asked Oct 23, 2019 ajaysoni1924 754 views answer comment Share Follow See all 6 Comments See all 6 6 Comments reply Naveen Kumar 3 commented Oct 23, 2019 reply Follow Share (a) 0.176 (b) 0.118 ?? 0 votes 0 votes techbd123 commented Oct 23, 2019 reply Follow Share Naveen Kumar 3 There is an decidability with the probability $p$ for each day. It means that the answer should contain the formula having $p$. 3 votes 3 votes Naveen Kumar 3 commented Oct 24, 2019 reply Follow Share Oh.. then probability of getting head will be p/2 ,& probability of not getting head will be (1-p/2). So, (a) $^{20}C_{10}(p/2)^{10}(1-p/2)^{10}$ 2 votes 2 votes ajaysoni1924 commented Oct 24, 2019 reply Follow Share @Naveen Kumar 3Why we taking here p/2 0 votes 0 votes techbd123 commented Oct 24, 2019 reply Follow Share @Naveen Kumar 3 I also think so. 0 votes 0 votes Naveen Kumar 3 commented Oct 24, 2019 reply Follow Share @ajaysoni1924 each day we are first flipping a coin with probability p, then getting a head with probability 1/2. so, P(success)= p*(1/2) =p/2 {both are independent events} &, P(not success)= (1-p/2) 1 votes 1 votes Please log in or register to add a comment.