Problem PageQuestion The mass of a radioactive substance follows a continuous exponential decay model, with a decay rate parameter of per day. Find the half-life of this substance (that is, the time it takes for one-half the original amount in a given sample of this substance to decay).

Answers

Answer 1

Answer:

8.55 days for a decay rate parameter of 8.1% per day

Step-by-step explanation:

Assuming a decay rate parameter of  8.1% per day

the general equation for radioactive decay is;

N = N₀e^(-λt)

x - decay constant (λ) - rate of decay 

t-  time 

N - amount remaining after t days , since we are calculating the half life, amount of time it takes for the substance to to be half its original value, its N₀/2

N₀ - amount initially present 

substituting the values 

N₀/2 = N₀e^(-0.081t)

0.5 = e^(-0.081t)

ln (0.5) = -0.081t

-0.693 = -0.081t

t = 0.693 / 0.081  = 8.55

half life of substance is 8.55 days 


Related Questions

How did governments pursue mercantilist policies?

Answers

Answer:

Most of the mercantilist policies were the outgrowth of the relationship between the governments of the nation-states and their mercantile classes

Step-by-step explanation:

In the British empire Mercantilism, an economic policy designed to increase a nation's wealth through ... Mercantilism did, however, lead to the adoption of enormous trade

Hope this helps. :)

i have a daily allowance of 70grm but have only used 48 what percentage do i have left

Answers

Answer:

You have 31.43% of your allowance left.

Step-by-step explanation:

This question can be solved using a rule of three.

Your initial amount, of 70, is 100%.

The remaining amount, of 70 - 48 = 22, is x%. So

70 - 100%

22 - x%

[tex]70x = 100*22[/tex]

[tex]x = \frac{100*22}{70}[/tex]

[tex]x = 31.43[/tex]

You have 31.43% of your allowance left.

The mean of the data set(9,5,y,2,x)is twice the data set (8,x, 4,1,3).What is (y-x)

Answers

Answer:

y - x = 16

Step-by-step explanation:

Explanation:-

Step(i):-

Given data set A  is  9,5,y,2,x

Mean of the Data set A

                         =   [tex]\frac{9 + 5 + y + 2 +x}{5}[/tex]

                         = [tex]\frac{16 +x+y}{5}[/tex]

Given data set B is 8, x, 4, 1, 3

Mean of the Data set B

                         =   [tex]\frac{8+ x+4+1+3}{5}[/tex]

Step(ii):-                          

Mean of the Data set A  = 2 X Mean of the Data set B

              [tex]\frac{16 +x+y}{5} = 2 X \frac{16+x}{5}[/tex]

On simplification , we get

           16 +x + y = 2( 16 +x)

           16 + x + y = 32 + 2 x

            16 + x + y - 32 - 2 x = 0

            y - x -16 =0

           y - x = 16

A college student is interested in investigating the TV-watching habits of her classmates and surveys 20 people on the number of hours they watch per week. The results are provided below. Calculate the 80% confidence interval of the true average number of hours of TV watched per week.
P.S: excel formola needed only. For lower and Upper Bound
CBB K-6 4 3 6 6 0 9 4 5 5 8 8 7 4 8 89265 123456789 0123456789 20 2

Answers

Answer:

80% confidence interval of the true average number of hours of TV watched per week is [8.28 hours, 11.02 hours].

Step-by-step explanation:

We are given that a college student is interested in investigating the TV-watching habits of her classmates and surveys 20 people on the number of hours they watch per week. The results are provided below;

Hours of TV per week (X): 6, 14, 13, 6, 16, 10, 19, 4, 5, 5, 18, 8, 7, 14, 8, 8, 9, 12, 6, 5.

Firstly, the Pivotal quantity for 80% confidence interval for the true average is given by;

                                P.Q. =  [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex]  ~ [tex]t_n_-_1[/tex]

where, [tex]\bar X[/tex] = sample mean number of hours of TV watched per week = [tex]\frac{\sum X}{n}[/tex] = 9.65

            s = sample standard deviation = [tex]\sqrt{\frac{\sum (X -\bar X)^{2} }{n-1} }[/tex]  = 4.61

            n = sample of people = 20

           [tex]\mu[/tex] = true average number of hours of TV watched per week

Here for constructing 80% confidence interval we have used One-sample t-test statistics as we don't know about population standard deviation.

So, 80% confidence interval for the true average, [tex]\mu[/tex] is ;

P(-1.33 < [tex]t_1_9[/tex] < 1.33) = 0.80  {As the critical value of t at 19 degrees of

                                               freedom are -1.33 & 1.33 with P = 10%}  

P(-1.33 < [tex]\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }[/tex] < 1.33) = 0.80

P( [tex]-1.33 \times {\frac{s}{\sqrt{n} } }[/tex] < [tex]{\bar X-\mu}[/tex] < [tex]1.33 \times {\frac{s}{\sqrt{n} } }[/tex] ) = 0.80

P( [tex]\bar X-1.33 \times {\frac{s}{\sqrt{n} } }[/tex] < [tex]\mu[/tex] < [tex]\bar X+1.33 \times {\frac{s}{\sqrt{n} } }[/tex] ) = 0.80

80% confidence interval for [tex]\mu[/tex] = [ [tex]\bar X-1.33 \times {\frac{s}{\sqrt{n} } }[/tex] , [tex]\bar X+1.33 \times {\frac{s}{\sqrt{n} } }[/tex] ]

                                         = [ [tex]9.65-1.33 \times {\frac{4.61}{\sqrt{20} } }[/tex] , [tex]9.65+1.33 \times {\frac{4.61}{\sqrt{20} } }[/tex] ]

                                         = [8.28 hours, 11.02 hours]

Therefore, 80% confidence interval of the true average number of hours of TV watched per week is [8.28 hours, 11.02 hours].

Suppose parts are of two varieties: good (with probability 90/92) and slightly defective (with probability 2/92). Parts are produced one after the other. What is the probability that at least 3 parts must be produced until there is a slightly defective part produced

Answers

Answer:

95.69%

Step-by-step explanation:

We have X is the number of parts produced up to (and including) the first slightly defective part. So, X is Geometric (2/92), which would be the following:

P (X => 3) = Summation i = 3, up to infinity of {[(90/92)^(i-1)] * (2/92)}

We replace and solve and we are left with:

P (X => 3) = (2/92) * (90/92)^(3-1) * 1/(1 - 90/92)

P (X => 3) = 0.9569

Which means that the probability that at least 3 parts must be produced until there is a slightly defective part produced is 95.69%

Which expression is equivalent to 3(x-6)+5(x-4)

Answers

Answer:

[tex]8x-38[/tex]

Step-by-step explanation:

[tex]3(x-6)+5(x-4)\\3x-18+5x-20\\3x+5x-18-20\\8x-38[/tex]

evaluate...
(2/1) to the power -2

Answers

The answer is 0.25 or 1/4

Answer:

hope this helps :)

Step-by-step explanation:

1/4 because 2/1 is 2 and 2 to the power of -2 is 1/4

Let $A_1 A_2 A_3 A_4$ be a regular tetrahedron. Let $P_1$ be the center of face $A_2 A_3 A_4,$ and define vertices $P_2,$ $P_3,$ and $P_4$ the same way. Find the ratio of the volume of tetrahedron $A_1 A_2 A_3 A_4$ to the volume of tetrahedron $P_1 P_2 P_3 P_4.$

Answers

Answer:

  27 : 1

Step-by-step explanation:

The faces of a regular tetrahedron are equilateral triangles. The incenter, circumcenter, and centroid are all the same point, located 1/3 of the distance from the edge to the opposite vertex of the face. The vertical height of the point that is 1/3 the slant height from the base is 1/3 of the height of the tetrahedron.

Then the "inscribed" tetrahedron has 1/3 the height of the original. The ratio of volumes is the cube of the ratio of linear dimensions, so the ratio of the larger volume to the smaller is ...

  3³ : 1³ = 27 : 1

What are the next two numbers in the pattern of numbers;
45, 15, 44, 17, 40, 20, 31, 25, …

Answers

Answer:

Next two numbers are 15 and 32 respectively.

Step-by-step explanation:

The given pattern is  

45, 15, 44, 17, 40, 20, 31, 25, …

Here, we have two patterns.

Odd places : 45, 44, 40, 31,...

Even places : 15, 17, 20, 25,...

In series of odd places, we need to subtract square of integers.

[tex]45-(1)^2=45-1=44[/tex]

[tex]44-(2)^2=44-4=40[/tex]

[tex]40-(3)^2=40-9=31[/tex]

So, 9th term of given pattern is  

[tex]31-(4)^2=31-16=15[/tex]

In series of even places, we need to add prime numbers.

[tex]15-2=17[/tex]

[tex]17+3=20[/tex]

[tex]20+5=25[/tex]

So, 10th term of given pattern is  

[tex]25+7=32[/tex]

Therefore, the next two numbers in the pattern of numbers are 15 and 32 respectively.

The probability that an event will happen is P(E)=34. Find the probability that the event will not happen.

Answers

Answer:

.66

Step-by-step explanation:

1minus .34

Correct me if I am wrong

When writing expressions for complex numbers, what does i represent?

Answers

Answer: See below

Step-by-step explanation:

[tex]i[/tex] is an imaginary number.

[tex]i=\sqrt{-1}[/tex]

[tex]i^2=-1[/tex]

$17,500,000 is what percent of $70,000,000?

Answers

Answer: 1/4 of 70,000,000

Step-by-step explanation: 17,500,000 / 70,000,000 = 0.25

Answer:

[tex]25\%[/tex]

Step-by-step explanation:

[tex]\frac{17,500,000}{70,000,000}[/tex]

[tex]\frac{1}{4}=0.25=25/100=25\%[/tex]

Please help! Correct answer only, please! Find the following product if possible. Explain if it is not possible. A. B. C. D.

Answers

Answer:  A

Step-by-step explanation:

To multiply matrices, multiply each term in Row 1 of the first matrix with each term in Column 1 of the second matrix and then find their sum.  Repeat for Row1×Column2, Row2×Column1, and Row2×Column2.

[tex]\left[\begin{array}{ccc}1&4&-1\\3&2&2\end{array}\right] \times \left[\begin{array}{cc}2&-1\\0&3\\5&2\end{array}\right] \\\\\\=\left[\begin{array}{ccc}1(2)+4(0)-1(5)&1(-1)+4(3)-1(2)\\3(2)+2(0)+2(5)&3(-1)+2(3)+2(2)\end{array}\right] \\\\\\=\left[\begin{array}{cc}-3&9\\16&7\end{array}\right][/tex]

maths
Ella mixes cordial and water in the ratio of 1:4 how much water should be mixed with 50ml or cordial

Answers

200ml of water should be mixed

While filing your income tax, you report annual contributions of $100 to a public radio station, $300 to PBS (television station), $150 to a woman’s shelter, and $450 to other charitable organizations.

Find your monthly expense.

Answers

Hey there! I'm happy to help!

Let's add up all of these contributions.

100+300+150+450=1000

However, this is annual. We want monthly. So, we simply divide by 12.

1000/12≈83.33

Therefore, the monthly expense is $83.33

I hope that this helps! Have a wonderful day!

The currency in Bolivia is the Boliviano. The exchange rate is approximately $1 = 8 Bolivianos. At this rate, how many Bolivianos would you get if you exchanged $3?

Answers

Answer:

24 bolivianos

Step-by-step explanation:

$1=8b

$3=?

Cross multiply: ($3*8)/1 =24

write this small number in standard form. 0.00078

Answers

Answer:

78/100000

Hope it helps you

7.8^ -4 is scientific notation

Describe the solutions of the following system in parametric vector form,and provide a geometric comparison with the solution set .

x1 + 3x2- 5x3 = 4
x1+ 4x2 - 8x3 = 7
-3x1- 7x2 +9x3 =6

Answers

Answer:

The equations are linearly independent so there is no parametric vector form

Step-by-step explanation:

I attached the solution.

calculate the
Simple interest on a
7,500,00 for 4 years
at 4½
per
annum​

Answers

Step-by-step explanation:

S.i =principal x rate x time/100

7,50000x4x4.5/100

13500000/100

135000

PLEASE HELP ?


The range is the set of

A: first coordinates

B: ordered pairs

C:second coordinates

Answers

Answer:

C:second coordinates

Step-by-step explanation:

A range is the set of output coordinates

The domain is the input coordinates

Domain is the x, range is the y

Answer: its definitly c

Step-by-step explanation:

I need help with solving this

Answers

Answer:

49

Step-by-step explanation:

Positive 49 not -49

What is the perimeter of the shape below?

Answers

Answer:

I think it is 288.6 ft. Lol hope this helps

Step-by-step explanation:

x^2 + 5x - 24 = 0 How do I solve by factoring

Answers

Answer:

x = -8 or x = 3

Step-by-step explanation:

To factor ax² + bx + c, use AC method.

a times c is 1 × -24 = -24.

Factors of ac (-24) that add up to b (5) are 8 and -3.

Divide by a and reduce: 8/1 and -3/1.

Therefore, the factors are x + 8 and x − 3.

x² + 5x − 24 = 0

(x + 8) (x − 3) = 0

x = -8 or 3

Solve Systems of Algebraic Equations in Two Variables
Hello I need some help on setting up 2 equations of this problem. The answers are cheeseburger costs $1.55 and the milkshake $0.85

Four cheeseburgers and two chocolate milkshakes cost a total of $ 7.90. Two
Shakes cost 15 cents more than a hamburger with
cheese so What is the price of a cheeseburger?
And the price of a shake?

Answers

Answer:

4c+ 2m = 7.90

2m -.15 = c

Step-by-step explanation:

Let c = cheese burger

m = milkshake

4c+ 2m = 7.90

2m -.15 = c

Substitute into the first equation

4( 2m -.15) +2m = 7.90

Distribute

8m -.6 +2m = 7.90

Combine like terms

10m - .6 = 7.90

Add .6 to each side

10m = 7.90+.6

10m = 8.50

Divide by m

10m = 8.50/10

m = .85

Now find c

2m -.15 = c

2(.85) - .15=c

1.70-.15 = c

1.55 =c

The following are daily outputs from shift A and shift B at a factory.

Shift A: {77, 91, 82, 68, 75, 72, 85, 65, 70, 79, 94, 86}
Shift B: {68, 93, 53, 100, 77, 86, 91, 88, 72, 74, 66, 82}
Q. Compare the means of the shift outputs. The workers in the shift with the highest mean will earn a bonus. Which shift will earn the bonus?

Answers

Answer:

shift B

Step-by-step explanation:

shift a is 78.6 repeating

shift b is 79.3 repeating

mean is when you add them all then divide it by the numbers it has

Answer:

shift B

Step-by-step explanation:

To calculate the mean for a set of data, add all the numbers in that set, then divide by the number of data points in the set.

Here's a graph of a linear function. Write the
equation that describes that function.
Express it in slope-intercept form.
Enter the correct answer.

Answers

Answer:

Step-by-step explanation:

The formula is y = mx + b

m being the slope, rise over run. And b being the y-intercept. Right off the bat we can visually see the y-intercept is -4.

To find slope, we need to take two sets of coords and apply the slope fomula. The slope fomula is change in y divided by the change in x. The function itself is straight, so that means the slope will be the exact same no matter which points you choose.

(4, -1) and (8, 2) are coords on the line. Do 2 - (-1) to get 3. then do 8 - 4 to get 4. Finally, we just gotta do 3/4 which is simply [tex]\frac{3}{4}[/tex].

We have the slope of 3/4 and we have the y-intercept of -4. Just plug it in the standard formula of y = mx + b to get:

[tex]y=\frac{3}{4} x-4[/tex]

Which of the following numbers are in setA? Check all that apply.
A = {x | x is a positive, odd integer less than 7}
0
1
2
5
3

Answers

Answer:

1, 3, 5.

Step-by-step explanation:

The members of the set are {1, 3, 5}.

Note 0 is an even integer so is not included in the set.

Also 0 is neither negative or positive.

On hot, sunny, summer days, Jane rents inner tubes by the river that runs through her town. Based on her past experience, she has assigned the following probability distribution to the number of tubes she will rent on a randomly selected day.

x 25 50 75 100 Total
P(x) 0.16 0.36 0.38 0.10 1.00

Find the probability expressions: (Round your answers to 2 decimal places.)

a. P(X=50)P(X=50).
b. P(X≤75)P(X≤75).
c. P(X>50)P(X>50).
d. P(X<100)P(X<100).

Answers

Answer:

a. P(X=50)= 0.36

b. P(X≤75) =  0.9

c. P(X>50)=  0.48

d. P(X<100) = 0.9

Step-by-step explanation:

The given data is

x                      25        50       75        100          Total

P(x)                0.16       0.36    0.38    0.10          1.00

Where X is the variable and P(X) = probabililty of that variable.

From the above

a. P(X=50)= 0.36

We add the probabilities of the variable below and equal to 75

b. P(X≤75) = 0.16+ 0.36+ 0.38= 0.9

We find the probability of the variable greater than 50 and add it.

c. P(X>50)= 0.38+0.10=  0.48

It can be calculated in two ways. One is to subtract the probability of 100 from total probability of 1. And the other is to add the probabilities of all the variables less than 100 . Both would give the same answer.

d. P(X<100)= 1- P(X=100)= 1-0.1= 0.9

linear function for f(-11)=5, slope of f= -2/3

Answers

Answer:

  f(x) = -2/3(x +11) +5

Step-by-step explanation:

The point-slope form of the equation of a line will give you the desired linear function:

  y = m(x -h) +k . . . . . for slope m through point (h, k)

You are give point (x, f(x)) = (-11, 5) = (h, k), and you are given slope m = -2/3. Putting these values into the function form gives ...

  f(x) = -2/3(x +11) +5

The probability of randomly selecting a white flower from a garden that has green, pink, yellow, and white flowers is 6%.

Which of the following describes the likelihood of selecting a white flower?
A.
likely
B.
unlikely
C.
neither unlikely nor likely

Answers

Answer:

b. unlikely

Step-by-step explanation:

I don't really know a step by step explanation :( sry

Unlikely because 50% would be c and anything above 50% would be a
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