The probability that a cell will fuse in the presence of polyethylene glycol is 1/2/ Let Y denote the number of cells exposed to antigen-carrying lymphocytes to obtain the first fusion. Use the method of Exercise 17 to find E[Y] Exercise 17: The probability p of being able to log on to a computer from a remote terminal at any given time is 7. Let X denote the number of attempts that must be made to gain access to the computer. Find EIX]. Can you express E[X] in terms of p? Hint. The series 1- (7)(3) E[X] is hot geometric To find E[X], expand this series and the series 3E[X] Subtract the two to form the series .7E[X] Evaluate this geometric series, and solve for E[X]