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

Math | Problem Solving and Data Analysis |

PSAT | PSAT Math Diagnostic |

PSAT Math | Math Diagnostic |

five percent each hour If there are ten salmonella at

times zero which of the following graphs models the population

growth reign of salmonella in the petri dish And here

the potential answer all right with sound effects No Right

those each breath We sure hope these people are wearing

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

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

since the last time we visited a public swimming pool

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

bit Instead of the experiment described in this paragraph here

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

rate with the equal live The amount of bacteria in

the petri dish doubled every hour In other words it

multiplied by one hundred percent at every interval But the

salmonella is a slow worker at least by comparison It

only multiplies by seventy five percent of each interval Well

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

when the experiment is started there are ten lonely salmonella

bacteria so we should make zero ten appoint on our

graph And guess what One of our answer choice is

already out of the running After one hour there will

be seventy five percent more salmonella while seventy five percent

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

how to get there by the way you can simply

multiply ten by point seven Five decimal version of seventy

five percent So on average there will be seven point

five mohr salmonella bacteria after that first hour or seventeen

point five total Well this is an average keep in

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

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

bacteria is a whole one and rounded up to eighteen

Then we should see another point at one eighteenth Right

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

so that one can go out the window What about

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

point five that we had after one hour No need

around just yet And multiply that by seventy five percent

of point Seven Five to get thirteen point one two

Five Adding that thirteen point one to five to the

seventeen point five from the first hour we get thirty

point six to five and now we can round up

thirty one There should be another point on our graphic

to thirty one Well it looks like both cnd have

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

to plot one more to find our answer Well after

three hours there should be roughly fifty for salmonella and

this is how we get there Thirty point Sixty five

point seven five twenty two point nine six eight seven

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

we get fifty three point five nine three seven five

which we round two fifty four Well graph C is

way off at point three Eighty no serene on even

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

point at three fifty four and we have a winner

Salmonella dinar muchas you could be a winner when your

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