Final answer:
The given pdf is a discrete pdf. Additional information is required to calculate specific probabilities.
Step-by-step explanation:
The given probability density function (pdf) of x is defined as x f(x) = c/x for x > 0.
In this case, x takes on the values 0, 1, 2, 3, 4, and 5. The given pdf is a discrete pdf because the values of x can be counted. Additionally, each probability P(x) is between zero and one, and the sum of the probabilities is one.
To find the probability P(x = 10), P(x = 20), and P(x ≤ 5), we would need more information or additional steps.