1. 1. A box contains 10 red balls and 5 green balls. If two balls are drawn at random, without replacement, what is the probability that both balls are red?

2. 2. A survey of 200 students showed that 120 of them own a smartphone and 80 of them own a laptop. If 50 of the students own both a smartphone and a laptop, what is the probability that a randomly chosen student owns at least one of these devices?

3. 3. A bag contains 4 blue balls, 6 red balls, and 5 green balls. If three balls are drawn at random, without replacement, what is the probability that at least two of them are red?

4. 4. A coin is tossed 10 times. What is the probability of getting at least 8 heads?

5. 5. The heights of a group of students are normally distributed with a mean of 170 cm and a standard deviation of 10 cm. If 5% of the students are taller than 185 cm, what is the minimum height a student must have to be in the top 5% of the class?