Q1) 設事件 E 代表 the first ball drawn is blue, 事件 F 代表 the second drawn is red. P{E∩F} = 2/5 × 3/4 = 3/10 P{F} = P{E∩F} + P{E'∩F...
...12, so y = 48/12 = 4. (b) The number of black balls is 48 - x - y = 48 - 3 - 4... number be n. After taking out n black balls, there are (48 - n) ...