One card is drawn at random from 100 cards numbered 1 to 100. What is the probability that the number is a perfect square?

Difficulty: Easy

Correct Answer: 1/10

Explanation:

Introduction / Context:Perfect squares ≤ 100 occur at n^2 for n = 1,…,10. The sample space contains 100 equally likely outcomes. We count and divide.

Given Data / Assumptions:

  • Numbers 1 to 100 equiprobable.
  • Squares: 1,4,9,16,25,36,49,64,81,100.

Concept / Approach:Count favorable outcomes, then compute probability = favorable / total.

Step-by-Step Solution:

Favorable squares = 10.Total outcomes = 100.Probability = 10/100 = 1/10.

Verification / Alternative check:Because 100 = 10^2, there are exactly 10 perfect squares up to 100. The list confirms the count.

Why Other Options Are Wrong:1/5 (= 0.2) and 2/5 (= 0.4) overestimate; “None of these” is unnecessary as 1/10 is exact.

Common Pitfalls:Including 0 (not in range) or omitting 100 (which is 10^2).

Final Answer:1/10

More Questions from Probability

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion