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Determine whether outcomes are impossible or certain to occur.

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a)

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We are told that a fair, $6$-sided die is thrown.

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The sides on a fair, $6$-sided die are numbered $1$ to $6$. There is no $7$ on such a die.

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Therefore, there is no chance of the die landing on a $7$, which means that the probability of the die landing on a $7$ must be $0$.

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Hence, this is an impossible event.

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b)

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We are told that a teacher chooses a student at random from a class of $20$ girls.

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The key piece of information to notice here is that the teacher's class is comprised of $20$ girls. Everybody in the class is a girl.

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Therefore, the student that the teacher randomly chooses from the class must be a girl, which means that the probability that the student chosen is a girl is $1$.

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Hence, this is a certain event.

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Probability is the chance that an event will occur.

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A certain event is an event that will definitely happen and therefore has a probability of $1$.

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An impossible event is an event that will never happen and therefore has a probability of $0$. 

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A fair $6$-sided die is rolled. The probability that the die lands on a $\\var{dice}$ is [[0]]. Therefore, we say that this event is [[1]].

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A teacher chooses a student at random from a class of $\\var{students}$ girls. The probability that the student chosen is a girl is [[0]]. Therefore, we say that this event is [[1]].

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