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If I have 5 crayons (red, orange, yellow, green, blue) and I randomly choose 4, what are the chances that I do NOT choose green?

Answer 1

#1/5#

We have five crayons, one of which is green. If I choose four crayons at random, what are the odds of not picking the green one?

First, let's find the number of ways I can choose four crayons from the five available. This is a combinations problem (the order we pick the crayons doesn't matter). The general formula for a combination is:

#C_(n,k)=(n!)/((k)!(n-k)!)# with #n="population", k="picks"#

#C_(5,4)=(5!)/((4)!(5-4)!)=5#

Of those 5, there's only 1 way to pick crayons that don't have green (red, orange, yellow, blue). So there's only a #1/5# probability of picking 4 crayons without getting a green.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.