What is the probability of getting a prime number between 10 and 30?

From 10 to 30, there are 21 numbers.

Six of them are prime numbers: 11, 13, 17, 19, 23, and 29.

If you pick a number at random from 10 to 30, the probability

that it's a Prime number is

6/21 = 2/7 = 28.57% (rounded)