Mathematics for IGCSE & O level - Probability (Section 4 - No. 35)
What is the probability of drawing a red ball on the first draw, not replacing it, and drawing a yellow ball on the second draw if there are 7 red balls and 3 yellow balls?
7/30
3/10
21/100
7/15
解释
(7/10) * (3/9) = 21/90 = 7/30.