The amount of time in minutes that it takes for a randomly selected customer to finish checking out their groceries is a continuous uniform random variable(that is to say it follows a uniform distribution) on the interval 0 to 5 minutes. That is to say that f(x) = 1/5 = 0.2 for x in (0,5) and 0 otherwise.

What is the probability that a randomly selected customer will take more than 3 minutes to check out their groceries?

What is the probability that a randomly selected customer will take exactly 3 minutes to check out their groceries?

Now say you sample 10 independent customers. What is the probability that exactly 5 of them will take more than 3 minutes to check out their groceries?

Now say you sample 10 independent customers. What is the probability that less than or equal to 5 of them will take more than 3 minutes to check out their groceries?