A jar contains m red balls and n black balls. The document defines probabilities for drawing balls from the jar: a) The probability the first ball drawn is red is m/(m+n). b) The probability the second ball is black given the first was red is [m/(m+n)]*[n/(m+n-1)]. c) The probability the first ball is red and the second is black is [n/(m+n)]*[m/(m+n-1)].