Suppose that after an operation, the electrical charge remaining on a circuit component has a uniform distribution between 50 and 100 and that these charges are independent of each other for different operations. If the machine is operated five times, find a. The probability that the residual charge is between 50 and 70 precisely two times? b. The mean and the standard deviation for the number of times the residual charge exceeds 75. c. If we are interested in charges that exceed 70. What is the probability that the first interest occurs in the fourth attempt