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A deck of cards contains cards numbered from one to 81.
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If a card is picked at random, what is the probability of picking a card that is divisible by five?
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So let’s consider this deck of cards.
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The cards are numbered from one to 81.
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Because we’re considering the probability of picking a card or a particular type of card, we can use this equation.
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The probability of an event is equal to the number of possible outcomes over the total number of outcomes.
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So in this question, the probability of picking a card which is divisible by five is equal to the number of card values which are divisible by five over the total number of cards.
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Let’s remember what it would mean for a value to be divisible by five.
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Any value that’s divisible by five means that we can divide that value by five and get an integer solution.
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An alternative way of thinking about it would be the values which are in the five times tables.
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We can list all the values here which are divisible by five.
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The first one would be five.
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The second one would be 10.
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And we can continue until we get to the final one of 80.
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We can’t go any higher because the cards only go up to 81.
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When we count up these values, there are 16.
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That means that the number of card values that are divisible by five is 16, and the total number of cards must be 81.
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We can’t simplify this fraction any further.
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So the probability of picking a card that is divisible by five is 16 over 81.