Someone is asked to take a number from 1 to 100. The probability that it is a prime is
\(\dfrac{1}{5}\)
\(\dfrac{6}{25}\)
\(\dfrac{1}{4}\)
\(\dfrac{13}{50}\)
Step 1: Probability means
\[ P(E) = \dfrac{\text{Number of favourable outcomes}}{\text{Total number of outcomes}} \]
Step 2: Here, the experiment is: choosing one number from 1 to 100.
Total outcomes = 100 (because there are 100 numbers from 1 to 100).
Step 3: Favourable outcomes = numbers that are prime.
Prime numbers are those which have exactly 2 factors: 1 and itself.
Step 4: Count prime numbers between 1 and 100. There are 25 prime numbers in this range.
Step 5: So, probability = \( \tfrac{25}{100} \).
Step 6: Simplify the fraction: \( \tfrac{25}{100} = \tfrac{1}{4} \).
Final Answer: Option C (\( \tfrac{1}{4} \)).