PSAT 1.18 Math Diagnostic

PSAT 1.18 Math Diagnostic. Which of the following graphs models the population growth rate of Salmonella in the petri dish?

MathProblem Solving and Data Analysis
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PSAT MathMath Diagnostic

Transcript

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five percent each hour If there are ten salmonella at

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times zero which of the following graphs models the population

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growth reign of salmonella in the petri dish And here

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the potential answer all right with sound effects No Right

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those each breath We sure hope these people are wearing

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masks or has mad suit's or something like that E

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coli salmonella We haven't seen anyone so surrounded by bacteria

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since the last time we visited a public swimming pool

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Okay so basically they're changing it up on us a

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bit Instead of the experiment described in this paragraph here

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they're using a different bacteria that multiplies at a different

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rate with the equal live The amount of bacteria in

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the petri dish doubled every hour In other words it

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multiplied by one hundred percent at every interval But the

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salmonella is a slow worker at least by comparison It

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only multiplies by seventy five percent of each interval Well

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let's start with what we know at times zero iii

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when the experiment is started there are ten lonely salmonella

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bacteria so we should make zero ten appoint on our

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graph And guess what One of our answer choice is

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already out of the running After one hour there will

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be seventy five percent more salmonella while seventy five percent

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of ten is seven point five if we're not sure

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how to get there by the way you can simply

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multiply ten by point seven Five decimal version of seventy

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five percent So on average there will be seven point

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five mohr salmonella bacteria after that first hour or seventeen

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point five total Well this is an average keep in

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mind so we're probably not going to see half a

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salmonella looking around here So let's assume that point five

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bacteria is a whole one and rounded up to eighteen

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Then we should see another point at one eighteenth Right

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radio And there isn't such a point in graft b

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so that one can go out the window What about

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an hour after that We'll go back to our seventeen

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point five that we had after one hour No need

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around just yet And multiply that by seventy five percent

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of point Seven Five to get thirteen point one two

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Five Adding that thirteen point one to five to the

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seventeen point five from the first hour we get thirty

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point six to five and now we can round up

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thirty one There should be another point on our graphic

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to thirty one Well it looks like both cnd have

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got a point in the general vicinity so we'll have

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to plot one more to find our answer Well after

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three hours there should be roughly fifty for salmonella and

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this is how we get there Thirty point Sixty five

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point seven five twenty two point nine six eight seven

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five ad that's who are thirty point sixty five and

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we get fifty three point five nine three seven five

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which we round two fifty four Well graph C is

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way off at point three Eighty no serene on even

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close The graf de and knows what's up here's a

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point at three fifty four and we have a winner

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Salmonella dinar muchas you could be a winner when your

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lab is overrun by a strain of bacteria that can 00:03:12.89 --> [endTime] cause typhoid fever No