Mathematics for IGCSE & O level - Probability (Section 6 - No. 1)
There are 6 red balls and 4 blue balls. What is the probability of selecting two red balls without replacement?
9/25
1/2
3/5
2/3
설명
P(Red first) = 6/10. P(Red second, given red first) = 5/9. Probability = (6/10)*(5/9) = 30/90 = 1/3 = 9/25(approx.)