Question: what is the probability of getting a prime number?
Answer: We divide the number of primes less than or equal to x by the number x. For example, to find the probability that a prime is selected from 1 to 10 requires us to divide the number of primes from 1 to 10 by 10. The numbers 2, 3, 5, 7 are prime, so the probability that a prime is selected is 4/10 = 40%.