Multiple choice

A box contains $20$ cards marked with the numbers $1$ to $20$. One card is drawn from this box at random. What is the probability that number on the card is a perfect square?

  1. $\dfrac{1}{5}$
  2. $\displaystyle \frac{2}{5}$
  3. $\displaystyle \frac{3}{5}$
  4. $\displaystyle \frac{4}{5}$
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A Correct answer
Explanation

Perfect squares between 1 and 20 are 1, 4, 9, 16. There are 4 such numbers. The probability is 4/20 = 1/5.

AI explanation

The sample space consists of 20 cards, so the total number of possible outcomes is 20. The perfect squares between 1 and 20 are 1, 4, 9, and 16, yielding 4 favorable outcomes. Using the classical probability formula, the probability is the number of favorable outcomes divided by the total outcomes: 4 divided by 20. Simplifying the fraction gives 1/5.

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