The rate at which a quantity M of a certain radioactive substance decays is proportional to the amount of the substance present at a given time. Which of the following is a differential equation that could describe this relationship?
1. dM/dt = -3.72 t^2
2. dM/dt = -0.11M
3. dM/dt = 0.08 t^2
4. dM/dt = 1.2M

Answers

Answer 1

Answer:

2. dM/dt = -0.11M

Step-by-step explanation:

Differential equations for proportional amouts:

A differential equation for proportional amounts is given by:

[tex]\frac{dx}{dt} = ax[/tex]

In which a is the constant rate. If the amount increases, a is positive. If it decays, b is positive.

In this question:

Decays, so a < 0.

Proportional to the amount of the substance present at a given time, which means that a multiplies the amount M.

This means that the correct answer is given by option 2.


Related Questions

debe tomar 4 fotos de una carrera. Cada vez que un corredor pasa a su lado, hay un 50% de probabilidad de que tome una foto de ese corredor. Además, para dos corredores cualesquiera, la probabilidad de que tome una foto de uno es independiente del otro. Una vez que obtenga 4 fotos, abandonará las instalaciones de la carrera y no intentará tomar más fotos. Si eres el sexto corredor en pasar al fotógrafo, entonces la probabilidad de que te tome una foto puede expresarse en la forma M / NM / N, donde MM y NN son números enteros positivos relativamente primos (es decir, su máximo común divisor es 1 ). Calcule M + NM + N.

Answers

Answer:

Ehhh waht ??im 10 jears old!

Step-by-step explanation:

Hahah

Estimate the sum of 8.43 + 8.12 + 7.98.

Answers

Answer:

we estimate it and get

the answer is 25.53

GIVING OUT BRAINLIEST ANSWER HELPPP ME QUICKKK PLSSS

Answers

Answer:

Number 2. Any circle can be mapped onto another circle by dilation then translation is FALSE

Step-by-step explanation:

What is 12÷2/5? Ty to everyone helping

Answers

Answer:

1.2 is the answer.

Step-by-step explanation:

12/2=6

6/5=1.3

Have a nice day!

2 3/4 + 12 6/8 = answer

Answers

Answer:

15 1/2

Step-by-step explanation:

Answer:

15 1/2

Step-by-step explanation:

Fifty students were surveyed and asked if they played sports and if they had a job. The table summarizes their responses.

Of the students who play sports, what percent do not have a job?

Answers

Answer: 10%

Step-by-step explanation: The percentage of 50-5 is 10%

Find the function h(x) = f(x) - g(x) if f(x)=3^x and g(x) = 3^2x - 3^x

Answers

Step-by-step explanation:

h(x)=f(x)-g(x)h(x)=3^x-3^2x-3^xh(x)=3^x(1-3²-1)h(x)=3^x(-9)h(x)= -27^x

hope it helps.

Adele's Voice:

"Hello, it's me. I was wondering if you could help me with this problem."

Don't send me a link to some website. I do trust it especially if it requires me to download something. Furthermore, Brainly will not accept links to random sites thus deleting the question along with taking away my points. :(

Answers

C! Find P(s)!!!!!!!!!!

Answer:

a) P(2) =3(2)=6

b) P(10)= 3(10)=30

c) P(s)= 3s

Step-by-step explanation:

P=3s/s =3

PLEASE HELP FAST

What is the probability of rolling two dice and getting a sum that is a multiple of 5 or
rolling doubles (dice land on the same number)?

Answers

Answer:

1/3

Step-by-step explanation:

Look in the figure and circle all double rolls and all sums that equal 10.

See pic below. Then count them. There are 12.

12/36 = 1/3

Jesse makes a large wooden picture frame in the shape of a rectangle with a diagonal brace on the back, as shown in the diagram.

What is the length, in feet, of the diagonal brace that Jesse uses?

Answer Choices:

F. 5ft

G.15ft

H.60ft

J.7ft

Answers

The answer is H.60ft

Answer:5 ft

Step-by-step explanation: ( 36 x 36 ) + ( 48 x 48 ) = 3600 inches

Square root of 3600 is 60

Convert inches to feet: 60 / 12 = 5

The coordinates of a rectangle, LMNO, are L(- 1,3), M(2,3), N(2, - 5), and 0(- 1,- 5).
a. What is the length and width of this rectangle?
b. What is the perimeter of the rectangle?
c. What is the area of the rectangle?

Answers

Answer:

length = 8; width = 3

perimeter = 22

area = 24

Step-by-step explanation:

L(- 1,3), M(2,3)

LM = |-1 - 2| = 3

M(2,3), N(2, - 5)

MN = |-5 - 3| = 8

length = 8; width = 3

perimeter = 2(L + W) = 2(8 + 3) = 22

area = LW = 8 × 3 = 24

Which is the most appropriate unit to measure the weight of salad ? A. Tons B. Ounces C. Teaspoons D. Pounds

Answers

Answer:

Ounces :)

Step-by-step explanation:

Find the distance between the pair of points. E(-5, 4) and F(3,4)

Answers

Answer:

8

Step-by-step explanation:

you use distance formula

A national study, that revealed a normal distribution, revealed that the average time a student spends studying statistics on a weekend is 60 minutes. A random sample of 11 students in BU 203 were asked to record their statistic study time over a weekend. The sample revealed an average study time of 44.27 minutes with a standard deviation of 20.4. With an alpha of 5% State the null hypothesis (H0) and the alternate hypothesis (H1). Draw the distribution.

Answers

Answer:

Null hypothesis = H0 : μ = 60

Alternative hypothesis = H1 : μ < 60

Step-by-step explanation:

From the question given :

μ = 60 minutes

xbar = 44.27 minutes

s = 20.4 minutes

The alternative hypothesis is the claim ; which is to hypothesize that the average studying time is 44.27 (which is less than the population average studying time)

The null hypothesis is the initial truth and it is the opposite of the alternative hypothesis.

The hypothesis are :

H0 : μ = 60

H1 : μ < 60

Question 8
Which property justifies the fact that 5(x - 2) is equivalent to 5x - 10?
commutative
associative
O distributive

Answers

It would be distributive since you distributed the 5 to x and -2.

5*x = 5x and 5*-2 = -10

Which is an equivalent way to express 3y

Answers

Answer:

3 f(x)

Step-by-step explanation:

this is very open-ended, (6y)/2 is equal to 3y

To estimate the benefits of an SAT prep course, a random sample of 10 students enrolled in the course is selected. For each of these students, their entrance score on the exam taken at the beginning of the course is recorded. Their exit score on the exam they take at the end of the course is recorded as well. The table displays the scores.

A 3-column table with 10 rows. Column 1 is labeled student with entries 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Column 2 is labeled Before with entries 800, 870, 860, 820, 1140, 1050, 850, 910, 830, 1140. Column 3 is labeled after with entries 1100, 1010, 1000, 980, 1410, 1270, 1020, 1010, 1060, 1340.

A 98% confidence interval for the mean difference (after – before) in score is 137.04 points to 248.96 points. Based on the confidence interval, is it reasonable to claim that the SAT prep course is beneficial?

No, 0 is not contained in the confidence interval.
Yes, 0 is not contained in the confidence interval.
No, the confidence interval only contains positive values.
Yes, the confidence interval only contains positive values.

Answers

Answer:

,, yes the confidence interval only contains positive values

Answer:

Yes, the confidence interval only contains positive values.

Step-by-step explanation:

A 98% confidence interval for the mean difference (after – before) in score is 137.04 points to 248.96 points.

Based on the confidence interval if we go though the table we will find that each student show increase in confidence level .

As, At least the confidence level improved because it contains positive values only if we subtract previous value with the new values.

Therefore ,Yes, the confidence interval only contains positive values.

Click here to know more about the confidence level.

https://brainly.com/question/15712887

#SPJ2

Use technology or a z-score table to answer the question.

The number of baby carrots in a bag is normally distributed with a mean of 94 carrots and a standard deviation of 8.2 carrots.

Approximately what percent of the bags of baby carrots have between 90 and 100 carrots?


23.3%

31.2%

45.5%

76.73%

Answers

Answer:

46% is the percent of the bags of baby carrots that have between 90 and 100 carrots

Step-by-step explanation:

The baby carrot is normally distributed.  

z = (x - µ)/σ

x is equal to number of baby carrots  

µ = mean

σ = standard deviation

Substituting the given values, we get -

90 ≤ x ≤ 100

z = (90 - 94)/8.2 = - 0.49

 For z value of -0.49, the probability is 0.31

For x = 100

z = (100 - 94)/8.2 = 0.73

For z value of 0.73, the probability is 0.77

P(90 ≤ x ≤ 100) = 0.77 - 0.31 = 0.46

The percent of the bags of baby carrots having carrots between 90 and 100 carrots is  0.46 × 100 = 46%

Which statement describes ?

The series diverges because it has a sum of 4.
The series converges because it has a sum of 4.
The series diverges because it does not have a sum.
The series converges because it does not have a sum.

Answers

Answer: B

The series converges because it has a sum of 4.

Step-by-step explanation:

The convergence or divergence of a series depends on the sum of the series and its common ratio. The series converges because its sum is b

The series is given as:

[tex]\sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n[/tex]

A geometric series is given as:

[tex]T_n = ar^{n-1}[/tex]

So, we rewrite the series as follows:

[tex]\sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n = \sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n[/tex]

Apply law of indices

[tex]\sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n = \sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^{n-1} \times (\frac{2}{3})[/tex]

Rewrite

[tex]\sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n = \sum\limits^{\infty}_{n=1} 2 \times (\frac{2}{3})(\frac{2}{3})^{n-1}[/tex]

[tex]\sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n = \sum\limits^{\infty}_{n=1} \frac{4}{3}(\frac{2}{3})^{n-1}[/tex]

So, we have:

[tex]T_n = \frac{4}{3}(\frac{2}{3})^{n-1}[/tex]

Compare the above series to: [tex]T_n = ar^{n-1}[/tex]

[tex]a = \frac{4}{3}[/tex]

[tex]r = \frac{2}{3}[/tex]

The sum of the series to infinity is:

[tex]S_{\infty} = \frac{a}{1 - r}[/tex]

So:

[tex]S_{\infty} = \frac{4/3}{1 - 2/3}[/tex]

[tex]S_{\infty} = \frac{4/3}{1/3}[/tex]

[tex]S_{\infty} = 4[/tex]

i.e. [tex]\sum\limits^{\infty}_{n=1} 2 (\frac{2}{3})^n = 4[/tex]

Also:

The common ratio (r)

[tex]r = \frac{2}{3}[/tex]

[tex]r = \frac{2}{3}[/tex] [tex]< 1[/tex]

When common ratio is less than 1, then such series is convergent.

Hence, (b) is true because it has a sum of 4

Read more about series at:

https://brainly.com/question/10813422

Do -16 and 16 have the same value

Answers

Answer:

No they do not

Step-by-step explanation:

16 is positive -16 is negative they have different values. Hope this helps!

no -16 and 16 does not have the same value


Rewrite in simplest terms: 0.1d – 0.5(8d – 10)

Answers

Answer:

...

Step-by-step explanation:

0.1d - 4d -5

Answer:

-3.9d-5

I believe this is the answer! Hope this helps!

Solve the equation 40 = -10(y+0.3). what does the y equal​

Answers

Answer:

y = -4.3

Step-by-step explanation:

40 = -10(y + 0.3) {Step 1: Use the distributive property to multiply -10 by y + 0.3}

40 = -10y + -10(0.3)

40 = -10y - 3 {Step 2: Add 3 to both sides.}

40 + 3 = -10y

43 = -10y {Step 3: Divide both sides by -10}

43/-10 = y

-4.3 = y

y equals -4.3.

Answer:

y = -4.3

Step-by-step explanation:

40 = -10(y + 0.3)

40 = -10y - 3

-3. -3

43 = -10y

Divide 43 by -10

y equal 4.3

I need the answer I just need DONT scam with a link

Answers

Answer:

==> C. , = 12x + 16x and 4(3x + 4x)

hope it helps

Undo the half of what was left amount. Multiply 2

Undo the spent $5 add $5

Undo the spent $8 Add $8

Answers

Answer:

the three numbers below are your answers. (in order)

Step-by-step explanation:

[tex]2*2=4\\4+5=9\\9+8=17[/tex]

what statement is not true about the absolute value of 6

Answers

where are the statements??

Answer:

I can't answer this sorry dude and next time show us the picture so that we can understand

Write the equation of the circle with the given information.
Center: (-8, 0)
Diameter: 5

Answers

Answer:

(x + 8)² + y² = 6.25

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r is the radius

Here (h, k ) = (- 8, 0 ) and r = 5 ÷ 2 = 2.5 , then

(x - (- 8))² + (y - 0)² = 2.5² , that is

(x + 8)² + y² = 6.25

Combine like term in the following expressions:
3x + 5y + 2z + 2x + y + 3z +5 -3
A. 18
B. 5x+6y+5z+2
C. 8x+$z+4y+8
D. None of Above​

Answers

Answer:

B. 5x+6y+5z+2

Step-by-step explanation:

3x + 5y + 2z + 2x + y + 3z +5 -3 = 5x +6y + 5z +2

B

5,8, 21, 17, 10, 11,5
What is the median of the set of numbers?

Answers

Answer:

10

Step-by-step explanation:

Rearrange in order, 5, 5, 8, 10, 11, 17, 21 and the median would be 10.

Find the volume for the regular pyramid.



V =

Answers

Answer:

What do you mean by that?

A sales manager collected data on annual sales for new customer accounts and the number of years of experience for a sample of 10 salespersons. In the Microsoft Excel Online file below you will find a sample of data on years of experience of the salesperson and annual sales. Conduct a regression analysis to explore the relationship between these two variables and then answer the following questions.
Open spreadsheet
Compute b1 and b0 (to 1 decimal).
b1 =____ fill in the blank
b0 =____ fill in the blank
Complete the estimated regression equation (to 1 decimal).
y= ____ + ____x fill in the blank 5x
According to this model, what is the change in annual sales ($1000s) for every year of experience (to 1 decimal)?
____fill in the blank
Compute the coefficient of determination (to 3 decimals). Note: report r2 between 0 and 1.
r2 =____ fill in the blank
What percentage of the variation in annual sales ($1000s) can be explained by the years of experience of the salesperson (to 1 decimal)?
fill in the blank ____ %
A new salesperson joins the team with 8 years of experience. What is the estimated annual sales ($1000s) for the new salesperson (to the nearest whole number)?
$____ fill in the blank
Salesperson Years of Experience Annual Sales ($1000s)
1 2 78
2 4 94
3 4 87
4 4 104
5 5 107
6 9 109
7 9 124
8 10 121
9 10 122
10 14 131

Answers

Answer:

(a) [tex]b_1 =3.4[/tex] and [tex]b_0 = 83.7[/tex]

(b) [tex]y=83.7+3.4 x[/tex]

(c) [tex]r^2 = 0.790[/tex]

(d) [tex]\% Variation = 79.0\%[/tex]

(e) The expected earnings is: $110,900

Step-by-step explanation:

The data for the 10 sales person is as follows:

[tex]\begin{array}{ccc}{Years\ of Experience} & {Annual\ Sales(\$ 1000)} & {Salesperson} & {1} & {1} & {85} & {2} & {3} & {97} & {3} & {3} & {95}& {4} & {5} & {97}& {5} & {7} & {105}& {6} & {8} & {106}& {7} & {10} & {122} & {8} & {10} & {120} & {9} & {12} & {113} & {10} & {12} & {134}\ \end{array}[/tex]

Required

Perform a regression analysis using Microsoft Excel

Note

I added two attachments to this solutionIn the first attachment, I highlighted the step to follow to perform regression analysis. At step 4, ensure that you fill in the input y range and the input x range. The input y range (in this question) is the column for sales person while the input x range is the annual sales Click ok, then Microsoft Excel will perform the analysis for you.

The question will be answered based on the result of the analysis performed by the application (See attachment 2)

See attachment 2 for the result of the analysis (I've highlighted the solution to each question on the attached file)

(a) b1 and b0

[tex]b_1 = 3.372767857[/tex]

[tex]b_1 \approx 3.4[/tex]

[tex]b_0 = 83.65625[/tex]

[tex]b_0 \approx 83.7[/tex]

(b) The estimated regression equation

The equation is of the form:

[tex]y =b_0 + b_1x[/tex]

Where:

[tex]b_1 =3.4[/tex]

[tex]b_0 =83.7[/tex]

So:

[tex]y=83.7+3.4 x[/tex]

(c) The coefficient of determination (r^2)

[tex]r^2 = 0.790361699[/tex]

[tex]r^2 \approx 0.790[/tex]

(d) Percentage of variation

To do this, we simply convert r^2 to percentage

[tex]\% Variation = r^2 * 100\%[/tex]

[tex]\% Variation = 0.790 * 100\%[/tex]

[tex]\% Variation = 79.0\%[/tex]

(e) Expected annual sales of a sales person with 8 years of experience.

Using the regression equation

[tex]y=83.7+3.4 x[/tex]

Where

[tex]x = 8[/tex] --- the years of experience.

So;

[tex]y = 83.7 + 3.4 * 8[/tex]

[tex]y = 83.7 + 27.2[/tex]

[tex]y = 110.9[/tex]

The expected earnings is: $110,900

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