A culture of the bacterium Salmonella enteritidis initially contains 50 cells. When introduced into a nutrient broth, the culture grows at a rate proportional to its size. After 1.5 hours, the population has increased to 775. (a) Find an expression for the number of bacteria after t hours. (Round your numeric values to four decimal places.)

Answers

Answer 1

Answer:

The expression for the number of bacteria after t hours is [tex]P(t) = 50e^{0.2922t}[/tex]

Step-by-step explanation:

When introduced into a nutrient broth, the culture grows at a rate proportional to its size.

This means that the size of the population, after t hours, is modeled by the following differential equation:

[tex]\frac{dP}{dt} = rP[/tex]

In which R is the growth rate.

The solution of this differential equation is:

[tex]P(t) = P(0)e^{rt}[/tex]

In which P(0) is the initial population.

A culture of the bacterium Salmonella enteritidis initially contains 50 cells.

This means that [tex]P(0) = 50[/tex], and so:

[tex]P(t) = P(0)e^{rt}[/tex]

[tex]P(t) = 50e^{rt}[/tex]

After 1.5 hours, the population has increased to 775.

This means that [tex]P(1.5) = 775[/tex]. We use this to find r. So

[tex]P(t) = P(0)e^{rt}[/tex]

[tex]500e^{1.5r} = 775[/tex]

[tex]e^{1.5r} = \frac{775}{500}[/tex]

[tex]\ln{e^{1.5r}} = \ln{\frac{775}{500}}[/tex]

[tex]1.5r = \ln{\frac{775}{500}}[/tex]

[tex]r = \frac{\ln{\frac{775}{500}}}{1.5}[/tex]

[tex]r = 0.2922[/tex]

The expression is:

[tex]P(t) = 50e^{rt}[/tex]

[tex]P(t) = 50e^{0.2922t}[/tex]

The expression for the number of bacteria after t hours is [tex]P(t) = 50e^{0.2922t}[/tex]


Related Questions

FREE POINT GIVE AWAY!!!!!! Just solve my equation 5*4+2=? (I already know the answer)

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Answer:

22

Step-by-step explanation:

I did the math in my head sooo if it's wrong I know why

Please help (No Links)

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Ok
First find something that will help you
($12 per hours)
(X is hours)
(Y is the money)

Next
To find y you must multiply each hours to $12.

Last:

X : 0 1 2 5

Y : ? ? ? ?
———————
X : 0(12) = 0 ( 0 hrs = $0)
1 (12) = 12 ( 1 hrs = $12)
2 (12) = 24 ( 2hrs = $24)
5(12) = 60 ( 5 hrs = $60)

Answer

0 = $0
1 = $12
2 = $24
5= $60

Equation ( I am not sure but I tried )

12x = y(total cost)

I hope this helped and was right,
Have a nice day.

Paul is selling $2 raffle tickets for his baseball team. He needs to sell at least
$230 worth of tickets to earn a team jacket. If he has already sold $50 worth of tickets, how many more raffle tickets, x, does Paul need to sell to earn a team jacket? ​

Answers

Answer: 90 more tickets

Step-by-step explanation:

230 - 50 = 180

180 divided by 2 = 90 tickets

Chris made his aunt a garden. The width is 7 2/5 ft and the length is 5 1/2 ft. What is the area of the garden?

Answers

Answer:

Hello! if Chris garden is a square shape then the answer is 40 7/10 in fraction form or 40.7 in decimal form

PLEASE HELP ILL GIVE BRAINLIEST !!! 100 POINTS !! NO FAKE ANSWERS !

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Step-by-step explanation:

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Find the value of x.
120°
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Answers

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Step-by-step explanation:

In ancient Egypt, mathematicians and architects used 10 as an approximation for π . The circular floor of an ancient arena is paved with tiles. The floor of the arena has a radius of 100 feet.

Answers

What is the question

Write each phrase as an algebraic expression.
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Answers

Given:

The given phrase is 16 seconds faster than Aya’s time.

To find:

The algebraic expression for the given phrase.

Solution:

Let x be the Aya’s time.

16 seconds faster than Aya’s time. It means 16 seconds less than Aya’s time.

We know that a negative sign "-" is used for less than.

16 seconds less than Aya’s time = [tex]x-16[/tex]

16 seconds faster than Aya’s time = [tex]x-16[/tex]

Therefore, the required algebraic expression is [tex]x-16[/tex].

How do we decide if a situation requires us to measure in square units or cubic units?

Answers

Answer: see below...

Step-by-step explanation:

Square units are when we are finding the surface area.

Since it is side x side, so ^2.

Cubic units are when we are finding the volume.

Since it is side x side x side, so ^3.

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Answers

Answer:

C - 129

Step-by-step explanation:

180-51=129

Discuss the political, economic and social organisation of buganda kingdom during the pre colonial period​

Answers

Answer:

What type of line the picture represent

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Surface Area=248 inches squared

You're playing a fantasy game that allows you to create your own character. There are 5 options for the
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possible outcomes?

Answers

Answer:

A i think

Step-by-step explanation:

-4t+ 14 = -9t+ 24
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Answer:

cncjdkgkejgksjckwjnviekfkwkckkdk kdkf

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The answer is 2rad3
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Answer:

102

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Answer:

15 square miles

Step-by-step explanation:

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Answer:

59

Step-by-step explanation:

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Answers

Speed= distance/ time

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What pre-reading strategy would help you determine which items or information might be important to learn?

Answers

Answer:

Discussion.  

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Step-by-step explanation:

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Answers

The coordinates for point A is (-2,-5)

Answer: -2,-5

Step-by-step explanation:

The red point is located in the 3rd quadrant in the graph. So that means both the y and the x are negative. So first you go by the x value, the point is located on the 2 space left (-) from the origin (center) of the graph and then you have to go 5 spaced down (-). So point A is located at (-2,-5).

Numbers 1, and 3 please

Answers

Answer:

  1.  shifts the graph right 2 units

  2. y = -2(x -3)² +7

Step-by-step explanation:

1) Replacing x with x-h in any function shifts the graph h units to the right. Here, you have replaced x with (x-2), so the graph will be shifted 2 units to the right.

__

3) The vertex form of the equation of a parabola is ...

  y = a(x -h)² +k . . . . . . . . for vertex (h, k) and vertical scale factor 'a'

Here, the vertex is (h, k) = (3, 7), and the parabola opens downward. This tells us the sign of 'a' is negative.

The graph is not so clear that it is easy to read the value of 'a' directly from it, but there are several clues.

The zeros of the above function are found at h±√(k/a). This graph shows the zeros to be located such that √(7/a) is slightly less than 2. This means the magnitude of 'a' will be slightly more than 7/2² = 1.75. The y-intercept of the function is 7-9a. It is less than -7, but probably more than -14. This puts bounds on 'a':

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------ × ------- =
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Answers

w^4 is the correct answer!!

Name the property that justifies the statement 17=17

Answers

Answer:

the property that justifies the statement 17=17 is equality

Step-by-step explanation:

because it shows that it is equal

17 Is equal to 17

Explanation:

They are equal

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My Answer:

Answers

i believe the answer is 2

find the volume of the solid formed by revolving the region bounded by the graphs of y = 4x - x^2 and f(x) = x^2 from [0,2] about the... a) x-axis.

Answers

Answer:

[tex]v = \frac{32\pi}{3}[/tex]

or

[tex]v=33.52[/tex]

Step-by-step explanation:

Given

[tex]f(x) = 4x - x^2[/tex]

[tex]g(x) = x^2[/tex]

[tex][a,b] = [0,2][/tex]

Required

The volume of the solid formed

Rotating about the x-axis.

Using the washer method to calculate the volume, we have:

[tex]\int dv = \int\limit^b_a \pi(f(x)^2 - g(x)^2) dx[/tex]

Integrate

[tex]v = \int\limit^b_a \pi(f(x)^2 - g(x)^2)\ dx[/tex]

[tex]v = \pi \int\limit^b_a (f(x)^2 - g(x)^2)\ dx[/tex]

Substitute values for a, b, f(x) and g(x)

[tex]v = \pi \int\limit^2_0 ((4x - x^2)^2 - (x^2)^2)\ dx[/tex]

Evaluate the exponents

[tex]v = \pi \int\limit^2_0 (16x^2 - 4x^3 - 4x^3 + x^4 - x^4)\ dx[/tex]

Simplify like terms

[tex]v = \pi \int\limit^2_0 (16x^2 - 8x^3 )\ dx[/tex]

Factor out 8

[tex]v = 8\pi \int\limit^2_0 (2x^2 - x^3 )\ dx[/tex]

Integrate

[tex]v = 8\pi [ \frac{2x^{2+1}}{2+1} - \frac{x^{3+1}}{3+1} ]|\limit^2_0[/tex]

[tex]v = 8\pi [ \frac{2x^{3}}{3} - \frac{x^{4}}{4} ]|\limit^2_0[/tex]

Substitute 2 and 0 for x, respectively

[tex]v = 8\pi ([ \frac{2*2^{3}}{3} - \frac{2^{4}}{4} ] - [ \frac{2*0^{3}}{3} - \frac{0^{4}}{4} ])[/tex]

[tex]v = 8\pi ([ \frac{2*2^{3}}{3} - \frac{2^{4}}{4} ] - [ 0 - 0])[/tex]

[tex]v = 8\pi [ \frac{2*2^{3}}{3} - \frac{2^{4}}{4} ][/tex]

[tex]v = 8\pi [ \frac{16}{3} - \frac{16}{4} ][/tex]

Take LCM

[tex]v = 8\pi [ \frac{16*4- 16 * 3}{12}][/tex]

[tex]v = 8\pi [ \frac{64- 48}{12}][/tex]

[tex]v = 8\pi * \frac{16}{12}[/tex]

Simplify

[tex]v = 8\pi * \frac{4}{3}[/tex]

[tex]v = \frac{32\pi}{3}[/tex]

or

[tex]v=\frac{32}{3} * \frac{22}{7}[/tex]

[tex]v=\frac{32*22}{3*7}[/tex]

[tex]v=\frac{704}{21}[/tex]

[tex]v=33.52[/tex]

Select the correct answer.
The number of books checked out at two different libraries each day this week are shown below. (at bottom)



How do the median number of books checked out each day compare?
A.
The median number of books checked out at Ryder is equal to the median number of books checked out at Williams.
B.
The median number of books checked out at Ryder is 23 more than the median number of books checked out at Williams.
C.
The median number of books checked out at Williams is 25 more than the median number of books checked out at Ryder.
D.
The median number of books checked out at Ryder is 18 more than the median number of books checked out at Williams.

Answers

Answer:

the answer is B.

Step-by-step explanation:

W= median is 58

R= median is 81

81-58=23

The median number of books checked out at Ryder is 23 more than the median number of books checked out at Williams.

What is Median?

The median is the value that's exactly in the middle of a data set when it is ordered. It's a measure of central tendency that separates the lowest 50% from the highest 50% of values. The steps for finding the median differ depending on whether you have an odd or an even number of data points

Arrange the data points from smallest to largest.

If the number of data points is odd, the median is the middle data point in the list.

If the number of data points is even, the median is the average of the two middle data points in the list.

Given data ,

Let the data of Williams be represented as W

Now , W = { 63 , 56 , 60 , 55 , 62 , 55 }

And , the data of Ryder be R

where R = { 80 , 75 , 82 , 84 , 82 , 79 }

And , the median of Williams = (56 + 60) / 2 = 58

And , the median of Ryder is = 81

So , the difference of medians = 81 - 58 = 23

Hence , median number of books checked out at Ryder is 23 more than Williams

To learn more about median click :

https://brainly.com/question/28687994

#SPJ2

saras bookshelf is 40cm long 50 cm wide and 900 mm high she wants to paint it and calculated its volume as 180000cm3 check if theres something wrong if yes show your working for correction

ill mark u

Answers

Answer:

The volume of the bookshelf is 180000 cm³.

Step-by-step explanation:

The dimensions of the bookshelf are 40 cm, 50 cm and 900 mm.

We know that,

1 mm = 0.1 cm

900 mm = 90 cm

Now the dimensions become 40 cm, 50 cm and 90 cm.

The volume of the bookshelf can be calculated as :

V = lbh

Substitute all the values,

V = 40 cm × 50 cm × 90 cm

V = 180000 cm³

So, the volume of the bookshelf is 180000 cm³.

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12 mi
What is the length of the hypotenuse?
miles

Answers

15..........................

2.52343454 + -34355343.99
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Answer:

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Step-by-step explanation:

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