Question

A marble is drawn from a bag containing 3 red marbles and 2 blue marbles and a number cube with faces numbered 1 through 6 is tossed. What is the probability that the marble drawn is blue and the number cube shows a number less than 3? A. 11/15 B. 1/4 C1/6. D. 2/15

Answer 1

Find sample space
step 1: pick one marbles from 5. there are 5 ways (5C1)
step 2: toss a cube one time, 1-6. there are 6 ways (6C1)

total ways (sample space) = 5x6 = 30
... multiplication rules

find event
step 1: pick one blue marbles from 2. there are 2 ways (2C1)
step 2: toss a cube one time, get only 1 or 2. there are 2 ways (2C1)

total ways for event = 2x2 = 4

p(event) = n(event)/n(sample space) = 4/30