A fair die with six sides labelled 1, 2, 3, 4, 5, 6, respectively, is to be randomly tossed repeatedly. After each toss, the score obtained will be recorded. (a) What is the probability that exactly 6 of the first 10 scores are even scores? (b) What is the expected number of even scores among the first 10 scores? (c) What is the probability that 10 tosses are required to obtain 6 even scores? (d) What is the expected number of tosses required to obtain 6 even scores? (e) Suppose the 9th even score is obtained on the 21st toss. What is the probability that the first 5 scores contain exactly 2 even scores?