Doing a bit of study for an interview. Came across this question: "n unbiased coins. What is the probability that half of them exactly are heads. Answer the question for n= 2, 3, 20000." My answers would be: n = 2: p(1h) = 0.5 n = 3: p(1.5h) = 0 n = 20000: p(10000h) = approx. 0 (close enough to a continuous random variable?) Do you agree/disagree? Also just checking another one: "2 fair dice. What is the probability of both showing six if I have observed at least one six." I would say the answer is 1/11 - working: (1*P(2 6's)/(1-P(0 6's))). Is that correct? Thanks for any advice! Nick.