A fair die is rolled. Event A is an even face and event B is a face below four. Given that the face is below four, what is the chance it is even?
AOne in two
BOne in three
COne in six
DTwo in three
Answer & Solution
Correct answer: B. One in three
1. A conditional chance shrinks the sample space to the outcomes that meet the condition.
2. Faces below four are 1, 2 and 3, so there are three outcomes to consider.
3. Among those three, the even faces are just 2.
4. So one of the three remaining outcomes is even.
5. The chance is therefore one in three.
6. Answering one in six uses the full six-sided sample space and ignores the condition.
7. Answering one in two uses the share of even faces on the whole die, which the condition has already changed.
_Source: OpenStax High School Statistics (CC BY 4.0), Ch 2 "Descriptive Statistics" and Ch 3 "Probability Topics", section 3.1 Terminology_
Related questions
An experiment whose result is not predetermined is called a:A conditional probability differs from an ordinary one because the count is divided by:On a fair six-sided die, the outcome of any one face is:A sample space can be represented by listing outcomes, by a Venn diagram, or by a:Sampling without replacement makes successive picks dependent because:Sampling with replacement means each member picked:Two events are independent when the outcome of the first:Independent and mutually exclusive are terms that: