A sample of 500 students during the fall semester shows that 300 took ECON 201, 220 took MATH 126, and 80 students took both at the same time. What is the probability that a student took ECON 201 or MATH 126.

At a local high​ school, 15​% of the students have blue eyes. Each​ day, 9​% of the​ blue-eyed students wear sunglasses on their way to​ school, while only 2​% of the students with​ non-blue eyes wear sunglasses.   Find the probability that a randomly selected student has blue eyes given that they wore sunglasses on their way to school.

The mosquitos are out in your back yard, and they bite you at random times. Each bite happens independently of the last bite. The average time between bites is 2.501 minutes. What is the probability that it takes longer than 1 minutes for them to first bite you?

If a seed is planted, it has a 80% chance of growing into a healthy plant. If 6 seeds are planted, what is the probability that exactly 2 don't grow?

For any day in July, there is a 20% chance of rainfall. An engineering construction company plans to cast a slabthat requires no rainfall during its casting period extending over 5 days. What is the probability of having no rainfallduring the casting period and one rainy day during the casting period?