Mathematics for IGCSE & O level - Probability (Section 7 - No. 21)
A box contains 3 blue and 5 red marbles. If one marble is selected at random, what is the probability that it is red?
3/8
5/8
3/5
1/8
คำอธิบาย
There are 5 red marbles out of a total of 8, so the probability is 5/8.