12. An electronic device has 18 French songs and 15 songs English speakers. We randomly select 10 songs to listen to during a training session. Determine the probability of selecting at least five French songs and four English songs.

13. An assessment consists of 20 multiple-choice questions. Every question offers four answer choices, only one of which is correct. Knowing that the student randomly answers the questions, determines the probability that he obtains a score of exactly 50%.

14. An experiment involves rolling two dice and observing the sum of the two numbers that appear on the top side of each die. If the sum is of 6, 8 or 10, we win $5. If the sum is 2, 3, 4, 5, 7, 9, 11 or 12, we loses $2.

a) Define a discrete random variable X for this experiment.

b) Use a table of values to establish the probability distribution of X.

c) If this experiment is repeated several times, what will be the gain, or loss, medium?

15. Among 200 electronic parts produced, 10% are defective. We take 10 pieces randomly to check them. Determine the probability that two coins chosen are defective.

16. An experiment involves tossing a coin 50 times and noting the number of times tails are obtained. Determines the probability of getting stacks 25 times or more.