Question

A bag contains

10
marbles:
4
are green,
2
are red, and
4
are blue. Linda chooses a marble at random, and without putting it back, chooses another one at random. What is the probability that both marbles she chooses are blue? Write your answer as a fraction in simplest form.

Answer 1

Probability on the first draw is (4 blue) / (10 marbles in the bag) = 4/10.

She doesn't replace the blue marble, so

Probability on the 2nd draw is (3 blue) / (9 marbles ion the bag) = 3/9.

Probability of BOTH events is

(4 · 3) / (10 · 9)

= (12) / (90)

= 2 / 15

= about 13.3% .