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Our size matters during a power outage phaen realizes that

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his flashlight needs to new triple a batteries Finn takes

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two batteries from a drawer containing an assorted selection of

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thirty batteries If thirty percent of these batteries are triple

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a what is the probability that both batteries finn selects

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will in fact be triple a Well isn't this problem

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absolutely delightful Any probability can be found by dividing the

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number of desired outcomes by the total number of outcomes

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possible right So that's in the numerator and that's the

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denominator right there are personal desired outcome would be a

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game of flashlight tag but let's figure out if we

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can get this thing working First start with the first

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battery that finn takes out of the drawer since the

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problem tells us that thirty percent of those thirty batteries

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are triple a Well we can calculate that there's a

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thirty percent chance that the first battery finn picks will

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be right Like nine out of thirty of those batteries

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being chosen Our trip lays right well once he picks

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his first battery Then there are twenty nine batteries to

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pick from but only eight of those will be right

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since he's already successfully drawn one of the correct batteries

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right these air too dependent events because the probability of

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picking one triple a battery on a draw changes after

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the first time finn goes into the drawer to find

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the probability that both batteries or triple a while we

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just apply the formula for calculating The probability of two

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deep and an events pva times p of b one

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say has occurred equals p of a and b And

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what does all that mean while we get nine over

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thirty times eight over twenty nine at seventy two over

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a lot and well bottom line is the fraction there

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is big and it's about point Oh eight to eight

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if you have a handy dandy calculator So since our

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answers were given in percentages we've have to convert that

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decimal into a percentage by multiplying it by a hundred

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percent And voila the correct answer is an eight point

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two eight percent Those don't look like great odds Looks

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like poor finn will be groping around in the dark

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for quite some time Let's Hope they're not The spiders 00:01:59.661 --> [endTime] look been there

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