Basic Probability Statistics Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

easy
A card numbered 1 through 10 is chosen at random. What is the probability that the number is prime?

Solution

  1. 1
    Step 1: The prime numbers from 1 to 10 are 2, 3, 5, and 7, so there are 4 favourable outcomes.
  2. 2
    Step 2: The probability is 410=25\frac{4}{10} = \frac{2}{5}.

Answer

25\frac{2}{5}
Basic probability is found by counting favourable outcomes and dividing by the total number of equally likely outcomes. Listing the prime numbers carefully prevents counting mistakes.

About Basic Probability

Probability is the measure of how likely an event is to occur, expressed as a number between 0 (impossible) and 1 (certain). It is calculated as the ratio of favorable outcomes to total possible outcomes when all outcomes are equally likely.

Learn more about Basic Probability →

More Basic Probability Examples

Example 1 easy

A bag contains 3 red, 5 blue, and 2 green marbles. What is the probability of drawing a blue marble?

Example 2 easy

A fair six-sided die is rolled. What is the probability of rolling an even number?

Example 3 easy

A spinner has 8 equal sections numbered 1–8. What is the probability of landing on a number greater

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