Question

In an basket, there are 20 eggs of four colors: red, black, yellow and blue. For each color, there are 5 eggs and they are numbered from 1 to 5.

1) If one egg is randomly drawn from the basket, what is the probability that the randomly selected egg is red or blue?

2) If one egg is randomly drawn from the basket, what is the probability that the randomly selected egg is numbered 1 or blue?

3) If two eggs are randomly drawn from the basket with replacement, what is the probability that the two randomly selected eggs are both blue?

4) If two eggs are randomly drawn from the basket without replacement, what is the probability that the two randomly selected eggs are both blue?

Answer 1

1) If one egg is randomly drawn from the basket, the probability that the randomly selected egg is red or blue = 10/20 = 0.5

2) If one egg is randomly drawn from the basket, the probability that the randomly selected egg is numbered 1 or blue = (5+3)/20 = 8/20 = 0.4

3) If two eggs are randomly drawn from the basket with replacement, the probability that the two randomly selected eggs are both blue = (5/20)² = 0.0625

4) If two eggs are randomly drawn from the basket without replacement, the probability that the two randomly selected eggs are both blue = 5C₂/20C₂ = 10/190 = 0.0526