The concentration of dichlorodiphenyltrichloroethane (DDT - an infamous pesticide) in Lake Michigan has been declining exponentially over many years. In 1971, the DDT concentration was 13.00 ppm (parts per million). In 1984, the DDT concentration was 2.22 ppm.


Using these data points, determine the exponential decay function to model the DDT concentration decline in terms of years, tt, where t=0t=0 represents the year 1971.


A) Write your function as y = Ce^{rt}y=Ce^rt. Round your value of rr to four decimal places.


B) Another way to write the function down is known as the half-life formula, written as y = C(0.5)^{t/H}y=C(0.5)^t/H, where HH is the time required for the concentration to get cut in half. Using the initial two data points, find the value of HH, rounded to 2 decimal places. Show all Algebraic work.


C) The goal was to reduce the DDT concentration to 0.98 ppm by 1995. Was this possible according to your model?

Answers

Answer 1

Answer: A) [tex]y=13e^{-0.1359t}[/tex]

              B) H = 5.10

              C) Yes

Step-by-step explanation: Exponential Decay function is a model that describes the reducing of an amount by a constant rate over time. Generally, it is written in the form: [tex]y(t)=Ce^{rt}[/tex]

A) C is initial quantity, in this case, the initial concentration of DDT. To determine r, using the data given:

[tex]y(t)=Ce^{rt}[/tex]

[tex]2.22=13e^{13r}[/tex]

[tex]e^{13r}=0.1708[/tex]

Using a natural logarithm property called power rule:

[tex]13r=ln(0.1708)[/tex]

[tex]r=\frac{ln(0.1708)}{13}[/tex]

[tex]r=-0.1359[/tex]

The decay function for concentration of DDT through the years is [tex]y(t)=13e^{-0.1359t}[/tex]

B) The value of H is calculated by [tex]y=C(0.5)^{\frac{t}{H} }[/tex]

[tex]2.22=13(0.5)^{\frac{13}{H} }[/tex]

[tex](0.5)^{\frac{13}{H} }=0.1708[/tex]

Again, using power rule for logarithm:

[tex]\frac{13}{H} log(0.5)=log(0.1708)[/tex]

[tex]\frac{13}{H} =\frac{log(0.1708)}{log(0.5)}[/tex]

[tex]\frac{13}{H} =2.55[/tex]

H = 5.10

Constant H in the half-life formula is H=5.10

C) Using model [tex]y(t)=13e^{-0.1359t}[/tex] to determine concentration of DDT in 1995:

[tex]y(24)=13e^{-0.1359.24}[/tex]

y(24) = 0.5

By 1995, the concentration of DDT is 0.5 ppm, so using this model is possible to reduce such amount and more of DDT.


Related Questions

Find x if f(x) = 2x + 7 and f(x) = -1.
a.5 b.-3 c.-4​

Answers

Answer:

Answer c. -4

Step-by-step explanation:

Equations

Given:

f(x) = 2x + 7

We need to find the value of x such that:

f(x) = -1

Equating:

2x + 7 = -1

Subtracting 7:

2x = -1 - 7

Operating:

2x = -8

Dividing by 2:

x = -8 / 2 = -4

x = -4

Answer c. -4

What is the value of a for the following circle in general form?
X^2+y^2+ax+by+c=0

Answers

Answer:

ANSWER: 8  A_P_E_X  

Step-by-step explanation:

Plug the radius and the center point into the equation, and convert it to general form to get your answer.

The value of a is 4.

What is the standard equation of a circle?

The standard equation of a circle is given by

(x -h)² + (y-k)² = r²

The equation given is

x² + y² +ax +by +c = 0

a = -h * 1

(h,k) represents the coordinate for the center of the circle

h = -4 , k =2

a = -(-4) *1 = 4

To know more about Standard Equation of a Circle

https://brainly.com/question/13658927

#SPJ2

not sure need help ​

Answers

Answer:

192

Step-by-step explanation:

There are 2 ways of solving for <4

The first is just to add the 2 angles not connected to <4

<4 = 51 + 51 = 102

The second is to find <2 and take that away from 180

<2 + 51 + 51 = 180

<2 = 180 - 102

<2 = 78

<4 + <2 = 180   (They are supplementary

<4 = 180 - 78

<4 = 102

6th grade math I mark as brainliest

Answers

Answer:FalseHope this helps!!

Answer:

false

Step-by-step explanation:

Exponents is basically that number multiplied by itself however many times the number on top is , so lemme just give a quick example, [tex]7^4[/tex] would be 7*7*7*7=2401

so

[tex]16^1[/tex] would just be sixteen  because any number to the power of 1 is that number

[tex]8^2[/tex] is 8*8 which gives us 64,

16 does not equal 64, so its

False

What is the solution to the inequality 7<=-3x-4

Answers

Answer:

The nearest option is -3 (negative 3)

So, Option B is correct.

Step-by-step explanation:

We need to solve the inequality [tex]7 \leq -3x-4[/tex]

Solving:

Step 1: Switching sides of inequality and reversing the inequality

[tex]-3x-4\geq 7[/tex]

Step 2: Adding 4 on both sides

[tex]-3x-4+4\geq 7+4\\-3x\geq 11[/tex]

Step 3: Dividing both sides by -3 and reversing the inequality

[tex]\frac{-3x}{-3}\leq \frac{11}{-3} \\x\leq -3.6\\[/tex]

The nearest option is -3 (negative 3)

So, Option B is correct.

On a coordinate plane, point B is at (negative 5, 2). B is located at (−5, 2). If B is reflected across the y-axis, the coordinates will be . If B is reflected across the x-axis, the coordinates will be .

Answers

Answer:

the anwser is (5,2) and  (-5,-2)

Step-by-step explanation:

Which inequality is true

Answers

C
The higher the negative number is the lesser it gets.

identify the equation of the line having a slope of -3 and a y- intercept of 7

A y + -3x +12
b y = 3x - 7
c y = 3 + 7
d y = -3x + 7

Answers

Answer:

D.

Step-by-step explanation:

We can use the slope-intercept form:

[tex]y=mx+b[/tex]

Where m is the slope and b is the y-intercept.

We know that the slope is -3.

And the y-intercept is 7.

Hence, we will substitute -3 for m and 7 for b. This yields:

[tex]y=-3x+7[/tex]

Therefore, our answer is D.

Add. Simplify the answer and write it as a mixed number. 7/18 + 2/9 + 5/6

Answers

Answer:

1 1/18

Step-by-step explanation:

Answer:

Decimal:1.4simple form:13/9 mixted:1 and 4/9

Step-by-step explanation:

The classic 60° triangle has a hypotenuse of length 2, an opposite side of length √3 and an adjacent side of length 1....find the value of Cos(60°)

Answers

Answer:

The trigonometric values for cos are C = A/H, which means that to find cos(60), you need to divide the adjacent side by the hypotenuse, which in this case gives you 1/2, so that is the value of cos(60).

I hope this helps!

Step-by-step explanation:

7 large tanks and 40 fish in each tanks how many fish on display

Answers

780 Srry if I’m wrong

Answer:

280

Step-by-step explanation:

All you have to do is 7x4 and look for how many 0's there are in the equation and add them on.

Can someone please help, ty!!
(Will mark brainliest)

Answers

Answer:

Arcadia

Step-by-step explanation:

the line in the box is the median and Arcadia is bigger than Millersburg

FIRST TO HELP IS BRAINLIEST

Answers

Answer:

(0,2)

Step-by-step explanation:

help me please reeeee​

Answers

Answer:4/5 and 2 3/5

Step-by-step explanation:

Pls help ASAP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! pls

Answers

2*8n*8n*8n*8n because 8n is the only part in () so 8n would considered the power of 4

Example 3.7.4: The sum of two positive numbers is 16. What is the smallest possible value of the sum of their squares

Answers

Answer:

The smallest possible value of the sum of their squares is 128.

Step-by-step explanation:

Let the first number = x

let the the second number = y

x +  y = 16

y = 16 -x

minimum value, f = x² + y²

f(x) = x² + (16-x)²

f(x) = x² + 256 - 32x + x²

f(x) = 2x² - 32x + 256

f(x)' = 4x - 32

4x - 32 = 0

4x = 32

x = 32 / 4

x = 8

The absolute minimum value of x = 8

y = 16 - x

y = 8

The smallest possible value of the sum of their squares is given by x² + y²;

=  (8)² + (8)²

= 128

Therefore, the smallest possible value of the sum of their squares is 128.

8/9+ (-5/6) divided by 1/6

Answers

Answer:

fraction answer: 3/4

decimal answer: 0.75

Mrs. Pearce conducted a survey in her class on the ages of famous people. The table below shows the results of her survey. Guess Actual Age 15 28 25 28 39 50 36 24 42 56 45 72 80 Which equations could best represent the line-of-best-fit for the given data set?​

Answers

Answer:

y=1.19x-4.3

Step-by-step explanation:

I did the math

Answer:

just here to steal some old points! sorry and thanks

Step-by-step explanation:

Help please ASAP will mark brainliest!!

Answers

-4 is the answer because when you have that it equals 2

Answer:

y=4x-7

Step-by-step explanation:

y=4x+6 (1,-3)

y=mx+b

m= 4 (1,-3)

y-(-3)=4(x-1)

y+3=4x-4

-3 -3

y=4x-7

Help meeeeeee! If it’s correct you will get a something good!

Answers

Answer:

24/4=6

Step-by-step explanation:

In the model, there are 4 rows of 6 blocks. 24 total blocks divided by the 4 rows gives you six objects in each row.

HTH :)

Write down step by step the process that you use
to solve multiplying a fraction by an integer.

Answers

Answer:

you place the 1 under the integer and follow the steps keep change it flip it . SO basically you keep the integer and the 1 and you change the sign to division and you place the numerator where the denominator is and the  denominator goes where the numerator is.

Step-by-step explanation:

Find the value of X. Geometry!!!

Answers

Answer:

D. 19

Step-by-step explanation:

x+5 has to equal half of the base(3x-9)

I tried everything else. Those answers didn't work. 3*19-9=48 and 19+5=24

48/2=24 Therefore, the answer is D, 19

Which statement best explains whether the table represents a linear or nonlinear function?
Input (x) −2 −5 −8 −11
Output (y) 7 4 1 −2
A It is a linear function because there is a constant rate of change in both the input and output values.

B It is a nonlinear function because there is a constant rate of change in both the input and output values.

C It is a linear function because the input values are decreasing.

D It is a nonlinear function because the input values are increasing.

Answers

Answer:

It is a linear function because there is a constant rate of change in both the input and output values.

Step-by-step explanation: I took the test

a submarine starts 800m below the surface of the ocean. It rises at a rate of 40m / min for 15 minutes. How much more does the submarine need to rise to reach 50m below the surface?

Answers

Correct me if I’m wrong. But the answer should be 18.75 minutes

How many oz. of a metal containing 40%
gold must be combined with 7 oz. of a
metal containing 90% gold to form an
alloy containing 75% gold?

Answers

Answer:

3 oz

Step-by-step explanation:

Let x represent the number of oz. of the medal with 40% gold:

Set up an equation and solve for x:

0.4x + 7(0.9) = 0.75(x + 7)

0.4x + 6.3 = 0.75x + 5.25

6.3 = 0.35x + 5.25

1.05 = 0.35x

3 = x

So, you will need 3 oz. of the metal with 40% gold

|2| + |-13| =

BRAINLIST AND EXTRA POINTS

Answers

Answer:

15

Step-by-step explanation:

|2| + |-13| =

2+13

15

Answer:

I think I might be 15

Step-by-step explanation:

I looked it up on google

The advertising sticker on Allen's
new car says it gets 36 miles per
gallon on the highway. The graph
represents the actual relationship
between the number of miles Allen
drove on the highway and the
gallons of gasoline his new car used.
How does the advertised gas
consumption rate compare to the
actual rate?

Answers

Answer:

Step-by-step explanation:

The rate in this case is slope of the line. The formula of a slope is m = [tex]\frac{y_{2} -y_{1} }{x_{2} -x_{1} }[/tex]  

(10, 325)

(4, 130)

m = [tex]\frac{325-130}{10-4}[/tex] = [tex]\frac{195}{6}[/tex] = 32.5 miles per gallon

The actual rate is less (better) than advertising.

If you have 3 cups of pineapple juice, how many total cups of lunch can you make?

Answers

About 6 that’s what I came up with

write an equation of the line that passes through (-1,3) and is parallel to the line y=2x+2

Answers

Answer:

y = 2x + 5

Step-by-step explanation:

y - 3 = 2( x + 1 )

y = 2x + 5

simply 3pq+5pr-2qr+qp-6rp​

Answers

Answer:

The answer is 4pq−pr−2qr

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