Video Transcript
What is the probability of rolling
a number greater than or equal to two on a regular die?
First, we remember the probability of
an event is equal to the number of ways the event can occur over the total possible
outcomes. Our event is rolling a number
greater than or equal to two. We want to show the number of ways
to roll a number greater than or equal to two over all possible numbers rolled.
If you think about a regular die,
we know that it’s a cube made of six faces. And the faces are numbered one,
two, three, four, five, six. Thinking about our event, we need
to determine how many of these faces are greater than or equal to two. Two is greater than or equal to
two. Three is greater than two. Four is greater than two. Five is greater than two and so is
six.
We have five outcomes greater than
or equal to two. The numerator for our probability —
the number of ways to roll a number greater than or equal to two — is five. What would be the denominator? How many possible outcomes are
there? How many different numbers could be
rolled? Because the die has six faces,
there are six possible outcomes. Our denominator equals six.
The probability of rolling a number
greater than or equal to two on a regular die is five out of six, five-sixths.
