Question

Below is a sample space for a family with 3 children. BGG stands for the oldest child being a boy, the middle child a girl, and the youngest a girl. Use the sample space to answer the question: What is the probability (in simplest form) that the oldest child is a a girl? _____Sample Space BBB BBG BGB BGG GBB GBG GGB GGG

Answer 1

Explanation

The probability that the oldest child is a girl is given by the quotient between two numbers:

- The number of combinations where a girl is the oldest child i.e. the number of elements in the sample space that start with a G.

- The total number of elements in the sample space.

The first number is 4 since we have 4 elements starting with G: GBB, GBG, GGB, GGG. The second number is 8. Therefore the probability that we are looking for is given by:

$P=\frac{4}{8}=\frac{1}{2}$Answer

Then the answer is 1/2.