Video Transcript
If I roll a regular six-sided die,
what is the probability that the score is divisible by three?
We’re told that this is a regular
six-sided die, which means that its faces show the integers from one to six. And the die is equally likely to
land on each face. When all the outcomes of an
experiment are equally likely, we can calculate the probability of a particular
event occurring by dividing the number of successful outcomes by the total number of
outcomes. In this example, where we’ve been
asked to find the probability that the score is divisible by three, the successful
outcomes are those numbers on the die that are divisible by three.
As we’ve already mentioned, because
this is a regular six-sided die, the possible outcomes are the integers from one to
six. There are therefore six possible
outcomes in total. The outcomes that are divisible by
three are those numbers that appear in the three times table, which are three and
six. So there are two successful
outcomes. The probability that the score is
divisible by three is therefore two out of six. This fraction can be simplified by
dividing both the numerator and denominator by two. And so our answer is one-third.
