Question

A bag contains 10

marbles:
are 3 green,
are 5 red, and
are 2 blue. Hans chooses a marble at random, and without putting it back, chooses another one at random. What is the probability that both marbles he chooses are red? Write your answer as a fraction in simplest form.

Answer 1

the answer is (5/10)*(4/9)=20/90= 2/9

because there are 5 red marbles out of a total of ten. if you take one out then there are 4 red marbles out of a total of 9. The probability of these events being in succession is the product of their probabilities.

any questions?