A number is chosen uniformly at random from {1, 2, 3, …, 50}. What is the probability that the chosen number is prime?

Introduction / Context:
Prime-counting over a small range is straightforward by enumeration or recalling standard lists up to 50. Probability equals (number of primes up to 50)/50 for uniform selection from 1–50.

Given Data / Assumptions:

• Sample space: integers 1 through 50 (size 50).
• Primes in this range are to be counted exactly once.

Concept / Approach:

• List primes ≤ 50.
• Compute probability = count / 50.

Step-by-Step Solution:

Verification / Alternative check:
Cross-check by excluding composites and 1; the remaining count remains 15, a standard fact set for small prime tables.

Why Other Options Are Wrong:

• 0.18, 0.24, 0.36 reflect incorrect prime counts.
• “None of these” is wrong because 0.30 is correct.

Common Pitfalls:

• Forgetting that 1 is not prime and that 49 (= 7^2) is composite.

Final Answer:
0.30