The​ half-life of a radioactive substance is 20 years. If you start with some amount of this​ substance, what fraction will remain in 180 years?

Answers

Answer 1

Answer:

1/512

Step-by-step explanation:

Let staring fraction = x

Half-life = 20 years ; this is the time taken for an element to decrease to half of its original size

Hence,

After 20 years - - - > x/2

After 40 years - - - - > x/2 ÷ 2 = x/2 * 1/2 = x /4

After 60 years - - - - > x/4 ÷ 2 = x/4 * 1/2 = x/8

After 80 years - - - - -> x/8 ÷ 2 = x/8 * 1/2 = x / 16

After 100 years - - - > x/16 * 1/2 = x/32

After 120 years - - - - > x/32 * 1/2 = x/64

After 140 years - - - - -> x / 64 * 1/2 = x / 128

After 160 years - - - - - > x / 128 * 1/2 = x/256

After 180 years - - - - > x/256 * 1/2 = x / 512

Hence, the fraction after 180 years = 1/512


Related Questions

Give the domain and range of G={(6.0),(-9,-3),(1,-3)}

Answers

Answer:

Step-by-step explanation:

D={ 6  , -9  , 1 }

R={  0  ,-3 }

Economists predict that Americans will spend $1,180 on electonics in
2020. this is a 6.8% increase from last year. What did Americans spend
last year?

Answers

Money spent by Americans last year=$1,180-6.8% of $1,180
=$1099.76

If my savings of $x grows 10 percent each year, how much will i have in 2 years?

Answers

Answer:

20 percent

Step-by-step explanation:

Each year is 10 percent so 10x2 or 10+10 will equal 20

On Monday, Main Street station sells 40 tickets.

There are four types of ticket; infant, child, adult and senior.

The bar chart shows the number of infant, child and adult tickets sold.


How many Senior tickets sold ?

Find how many adult tickets were sold than child tickets ?

BOTH QUESTION MUST BE ANSWERES

BEST ANS IS ALWAY MARKED BRAINLIST

NO FAKE

Answers

Answer:

How many Senior tickets sold ?

0

Find how many adult tickets were sold than child tickets ?

5

Step-by-step explanation:

Answer:

:];];]

u know

meeeeeeeeeeeeeeeeeeeeeeeeeeeee

brainlistttt

cutie

k?

Step-by-step explanation:

helpppp asap pleaseee

Answers

Answer:

29/3 is your answer

Step-by-step explanation:

pls mark as brainliest

The length of a rectangle is 10 yd less than three times the width, and the area of the rectangle is 77 yd^2. Find the dimensions of the rectangle.

Answers

Answer:

width = 7, length = 11

Step-by-step explanation:

area = 77

length = 3w - 10

width = w

w(3w - 10) = 77

3w^2 - 10w - 77 = 0

(3w + 11)(w - 7) = 0

we rule out 3w + 11 = 0 because w would be negative

so we use w - 7 = 0

so the width = 7

length = 3w - 10

length = 21 - 10

length = 11

the ages of two students are in the ratio of 3:5,if the older is 40yrs. How old is the younger student​

Answers

The ratio/proportion is young / old = young / old.

We know that one ratio is 3 / 5, so we need to complete the other.

3 / 5 = young / 40

5 goes into 40, 8 times, therefore we need to multiply the numerator by 8 also.

3 x 8 = 24

The younger student is 24 years old.

Hope this helps!

Answer:

24

Step-by-step explanation:

younger : older

3             :5

The older is 40

40/5 = 8

Multiply each by 8

younger : older

3 *8       :5 *8

24         : 40

The younger is 24

What is the x-intercept of the graph of the function f(x) = x2 − 16x + 64?

(−8, 0)
(0, 8)
(8, 0)
(0, −8)

Answers

Answer:

(8,0)

Step-by-step explanation:

f(x) = x^2 − 16x + 64

The x intercepts ( or zeros) are found by setting y=0

0 =   x^2 − 16x + 64

Factor

0 = (x-8)(x-8)

Using the zero product property

x-8 =0  x-8 =0

x=8   x=8

(8,0)

Answer:

8,0

edge 20201

Your credit card has a balance of $3300 and an annual interest rate of 14%. You decided to pay off the balance over two years. If there are no further purchases charged to the card, you must pay $158.40 each month, and you will pay a total interest of $501.60. Assume you decided to pay off the balance over one year rather than two. How much more must you pay each month and how much less will you pay in total interest?

Answers

9514 1404 393

Answer:

$137.90 more each month$246.00 less total interest

Step-by-step explanation:

The amortization formula is ...

  A = P(r/12)/(1 -(1 +r/12)^(-12t))

for the monthly payment on principal P at annual rate r for t years. Here, we have P=3300, r = 0.14, and t=1, so the monthly payment is ...

  A = $3300(0.14/12)/(1 -(1 +0.14/12)^-12) ≈ $296.30

The payment of $296.30 is ...

  $295.30 -158.40 = $137.90 . . . more each month

The total amount paid is 12×$296.30 = $3555.60, so 255.60 in interest. This amount is ...

  $501.60 -255.60 = $246.00 . . . less total interest

Which function describes this graph

Answers

Answer:

C.

Step-by-step explanation:

A P E X

Question 3 of 28
What is the length of IN in the right triangle below?
M
19
N
O A. 442
B. 442
O c. 1200
D. 280

Answers

Answer:

Option C. √280

Step-by-step explanation:

From the question given above, the following data were obtained

MN = 19

ML = 9

LN =?

We can obtain the value of LN by using the pythagoras theory as illustrated:

M ² = ML² + LN²

19² = 9² + LN²

361 = 81 + LN²

Collect like terms

361 – 81 = LN²

280 = LN²

Take the square root of both side

LN = √280

Therefore, the length of LN is √280

Find a vector v that is perpendicular to the plane through the points

A=(5,−4,4), B=(−5,0,−3), and C=(−4,2,−5).
v =

Answers

The value of vector v that is perpendicular to the plane through the points is,

⇒ v = (6, - 27, - 24)

What is Multiplication?

To multiply means to add a number to itself a particular number of times. Multiplication can be viewed as a process of repeated addition.

Given that;

Points are,

A = (5,−4,4), B = (−5,0,−3), and C = (−4,2,−5).

Hence, We get;

AB = [- 10, 4, - 7]

AC = [-9, 6, -9]

So, The value of vector v that is perpendicular to the plane through the points is,

⇒ v = AB x AC

⇒ v = (- 10, 4, - 7) x (- 9, 6, - 9)

⇒ v = (6, - 27, - 24)

Thus, The value of vector v that is perpendicular to the plane through the points is,

⇒ v = (6, - 27, - 24)

Learn more about the multiplication visit:

https://brainly.com/question/10873737

#SPJ2

To mail an envelope first class the us pot charges 0.32 cents for the first ounce and 0.24 cents for each additional ounce. Use an inequality to find the maximum number of whole ounces that can be mailed for $7.98

Answers

Answer:

Not sure about the inequality, but maximum ounces is 31 ounces.

Might be.

[tex]7.98 \geqslant .24x + .32[/tex]

Assuming that a 330-foot tall giant redwood grows vertically, if I walk a certain distance from the
tree and measure the angle of elevation to the top of the tree to be 69°, how far from the base of the
tree am I?
Round your answer to four decimal places.
I am about Number
feet away from the base of the tree.

Answers

9514 1404 393

Answer:

  126.6751 feet

Step-by-step explanation:

The tangent relation can be helpful.

  Tan = Opposite/Adjacent

  tan(69°) = (330 ft)/(distance to base)

  distance to base = (330 ft)/tan(69°) ≈ 126.6751 ft

_____

Comment on precision

It would make more sense to round to 4 significant figures. The value of a unit in the fourth decimal place is 0.0001 feet = 0.0012 inches, somewhat less than the thickness of a human hair. We know of no technology that will make a measurement of that distance to that accuracy.

Heeeelp pleasssse :D

Answers

Answer:

(x - 3/8)^2 = x^2 - 3/4x + 9/64

Step-by-step explanation:

Step-by-step explanation:

divide the number with x by 2 and get the square of that number and add that number to this given equation

number with x = -3/4

= x^2 - 3/4 x + 9/64

= (x -3/8) ^2

!!!!PLEASE HELP!!!!
What is the following quotient?
2
√13+ /11
O 13-2./11
13+ 11
6
13+ V11
12
√13 - 1

Answers

(D)

Step-by-step explanation:

Multiply and divide the fraction by the conjugate:

[tex]\dfrac{2}{\sqrt{13}+\sqrt{11}}×\dfrac{\sqrt{13}-\sqrt{11}}{\sqrt{13}-\sqrt{11}}[/tex]

[tex]= \dfrac{2(\sqrt{13} - \sqrt{11})}{(\sqrt{13})^2 - (\sqrt{11})^2}[/tex]

[tex]=\dfrac{2(\sqrt{13} - \sqrt{11})}{2}[/tex]

[tex]=\sqrt{13} - \sqrt{11}[/tex]

Farmers in one state produced 417,938,650 bushels of corn one year. If the production of corn decreases by ten million bushels, how many bushels of corn will be produced?


A 417,938,650 bushels

B 417,938,640 bushels

C 417,928,650 bushels

D 407,938,650 bushels

Answers

Answer:

D

Step-by-step explanation:

417,938,650-10,000,000=407,938,650

Answer:  D) 407,938,650 bushels

==========================================================

Explanation:

417,938,650 = 417 million, 938 thousand, 650

Focus on the "417 million" part only. Subtract 10 million from this, because of the key word "decrease". So we go from 417 to 417-10 = 407

Meaning we drop from 417 million to 407 million

The other parts remain the same

So "417 million, 938 thousand, 650" updates to "407 million, 938 thousand, 650"

Then we translate that somewhat wordy form into a pure number 407,938,650 which is choice D

In short, we just changed 417 to 407 and kept everything else the same.

Find the area of the shaded regions.

Answers

Answer: About 21.98 cm²

Step-by-step explanation:

First, find the area of the large shaded circle:

[tex]r^{2} \pi =3^{2} \pi =9\pi[/tex]

Find the area of the two small unshaded circles:

[tex]1) r^{2} \pi =1^{2} \pi =1\pi \\2) r^{2} \pi =1^{2} \pi=1\pi[/tex]

Subtract the area of the small circle from the large circle:

[tex]9\pi -1\pi -1\pi =9\pi -2\pi =7\pi[/tex]

Therefore, the area of the shaded region is:

[tex]7\pi =7*3.14=21.98[/tex]

Jordan buys sandals and sunglasses for a trip to the beach. The sunglasses cost $6. The sandals cost 3 times as much as the sunglasses. How much do the sandals cost?

Answers

We know that the sunglasses cost $6, and the sandals are 3 times as much. We can multiply 6*3 to get 18. The sandals cost $18.

Answer:

18 dollars

Step-by-step explanation:

sunglasses = 6 dollars

sandals = 3 * sunglasses

             = 3 * 6 dollars

             = 18 dollars

Assume that x and y are both differentiable functions of t. Find dx/dt when x=11 and dy/dt=-4 for the equation xy=99 .

Answers

Differentiating both sides of

xy = 99

with respect to t yields

x dy/dt + y dx/dt = 0

When x = 11, we have

11y = 99   ==>   y = 9

and we're given that dy/dt = -4 at this point, which means

11 (-4) + 9 dx/dt = 0   ==>   dx/dt = 44/9

A cyclist rides his bike at a speed of 21miles per hour. What is this speed in miles per minute? How many miles will the cyclist travel in 10 minutes?

Answers

Answer:

.35 miles per minute

3.5 miles in 10 minutes

Step-by-step explanation:

21 ÷ 60= .35

.35 × 10 = 3.5

an expression equivalent to 12+ 21 is

Answers

Answer:

33

Step-by-step explanation:

The answer is 1628. Because 16 x 21 = 28 x 12 = 336

Hope this helps

[tex]\lim_{x\to \ 0} \frac{\sqrt{cos2x}-\sqrt[3]{cos3x} }{sinx^{2} }[/tex]

Answers

Answer:

[tex]\displaystyle \lim_{x \to 0} \frac{\sqrt{cos(2x)} - \sqrt[3]{cos(3x)}}{sin(x^2)} = \frac{1}{2}[/tex]

General Formulas and Concepts:

Calculus

Limits

Limit Rule [Variable Direct Substitution]:                                                                     [tex]\displaystyle \lim_{x \to c} x = c[/tex]

L'Hopital's Rule

Differentiation

DerivativesDerivative Notation

Basic Power Rule:

f(x) = cxⁿ f’(x) = c·nxⁿ⁻¹

Derivative Rule [Chain Rule]:                                                                                    [tex]\displaystyle \frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)[/tex]

Step-by-step explanation:

We are given the limit:

[tex]\displaystyle \lim_{x \to 0} \frac{\sqrt{cos(2x)} - \sqrt[3]{cos(3x)}}{sin(x^2)}[/tex]

When we directly plug in x = 0, we see that we would have an indeterminate form:

[tex]\displaystyle \lim_{x \to 0} \frac{\sqrt{cos(2x)} - \sqrt[3]{cos(3x)}}{sin(x^2)} = \frac{0}{0}[/tex]

This tells us we need to use L'Hoptial's Rule. Let's differentiate the limit:

[tex]\displaystyle \lim_{x \to 0} \frac{\sqrt{cos(2x)} - \sqrt[3]{cos(3x)}}{sin(x^2)} = \displaystyle \lim_{x \to 0} \frac{\frac{-sin(2x)}{\sqrt{cos(2x)}} + \frac{sin(3x)}{[cos(3x)]^{\frac{2}{3}}}}{2xcos(x^2)}[/tex]

Plugging in x = 0 again, we would get:

[tex]\displaystyle \lim_{x \to 0} \frac{\frac{-sin(2x)}{\sqrt{cos(2x)}} + \frac{sin(3x)}{[cos(3x)]^{\frac{2}{3}}}}{2xcos(x^2)} = \frac{0}{0}[/tex]

Since we reached another indeterminate form, let's apply L'Hoptial's Rule again:

[tex]\displaystyle \lim_{x \to 0} \frac{\frac{-sin(2x)}{\sqrt{cos(2x)}} + \frac{sin(3x)}{[cos(3x)]^{\frac{2}{3}}}}{2xcos(x^2)} = \lim_{x \to 0} \frac{\frac{-[cos^2(2x) + 1]}{[cos(2x)]^{\frac{2}{3}}} + \frac{cos^2(3x) + 2}{[cos(3x)]^{\frac{5}{3}}}}{2cos(x^2) - 4x^2sin(x^2)}[/tex]

Substitute in x = 0 once more:

[tex]\displaystyle \lim_{x \to 0} \frac{\frac{-[cos^2(2x) + 1]}{[cos(2x)]^{\frac{2}{3}}} + \frac{cos^2(3x) + 2}{[cos(3x)]^{\frac{5}{3}}}}{2cos(x^2) - 4x^2sin(x^2)} = \frac{1}{2}[/tex]

And we have our final answer.

Topic: AP Calculus AB/BC (Calculus I/I + II)

Unit: Limits

A wedge of cheese is shaped like a triangular prism. The wedge of cheese is 7 inches tall. The base of the cheese is shaped like a triangle with a base of 11 and a height of 5 inches. If you ate this whole block of cheese, about how many cubic inches would you have eaten (ignoring the holes)?


420 in
193 in
385 in
210 in

Answers

Answer:

193 in

Step-by-step explanation:

Volume of a triangular prism:

The volume of a triangular prism is the base area multiplied by the wedge, that is:

[tex]V = A_bw[/tex]

The base area is one half times the triangle base times it's height, so:

[tex]V = 0.5*b*h*w[/tex]

The wedge of cheese is 7 inches tall.

This means that [tex]w = 7[/tex]

The base of the cheese is shaped like a triangle with a base of 11 and a height of 5 inches.

This means that [tex]b = 11, h = 5[/tex]

Volume:

[tex]V = 0.5*b*h*w = 0.5*11*5*7 = 192.5[/tex]

Rounding, approximately 193 in.

Just answer the questions please

Answers

Answer:

1)( y= 0.12 * x )             y(dependent) , x(independent)                                                                     2)  x=150 : y=18  /  x=300 : y=36  / x=450 : y=54  /  x=600 :   y=72  /  x=750 : y=90 / x=900 : y=108                                                                                                  3) 300+750+1050=2100 pound

 2100*0.12=252 pound food they need to eat in each day

252*7=1764 pound in each month

A certain test preparation course is designed to help students improve their scores on the LSAT exam. A mock exam is given at the beginning and end of the course to determine the effectiveness of the course. The following measurements are the net change in 6 students' scores on the exam after completing the course: 6,16,19,12,15,14.
Using these data, construct a 90% confidence interval for the average net change in a student's score after completing the course. Assume the population is approximately normal. Find the critical value that should be used in constructing the confidence interval.

Answers

Answer:

The critical value is [tex]T_c = 2.5706[/tex].

The 90% confidence interval for the average net change in a student's score after completing the course is (9.04, 18.30).

Step-by-step explanation:

Before building the confidence interval, we need to find the sample mean and the sample standard deviation:

Sample mean:

[tex]\overline{x} = \frac{6+16+19+12+15+14}{6} = 13.67[/tex]

Sample standard deviation:

[tex]s = \sqrt{\frac{(6-13.67)^2+(16-13.67)^2+(19-13.67)^2+(12-13.67)^2+(15-13.67)^2+(14-13.67)^2}{5}} = 4.4121[/tex]

Confidence interval:

We have the standard deviation for the sample, so the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 6 - 1 = 5

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 2.5706, that is, the critical value is [tex]T_c = 2.5706[/tex]

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 2.5706\frac{4.4121}{\sqrt{6}} = 4.63[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 13.67 - 4.63 = 9.04.

The upper end of the interval is the sample mean added to M. So it is 13.67 + 4.63 = 18.30.

The 90% confidence interval for the average net change in a student's score after completing the course is (9.04, 18.30).

g(x) = -8x + 2, find

a. g(x+4)

b. g(x) + g(-2)

Answers

Answer:

g(x+4)= -8(x+4)+2

=-8x-32+2=-8x-30

g(x)+g(-2)=-8x+2+(-8(-2)+2)

=-8x+2+(16+2)

=-8x+20

a.=-8x-30

b.=-8x+20

What is the domain of the function graphed below?

Answers

Answer:

A. x<7

Step-by-step explanation:

The point at x=7 is an open circle, so the sign is <, not ≤

[tex]f(x)=e^{3x} .sinx[/tex] . tính [tex]d^{2} f(0)[/tex]

Answers

Answer:

6

Step-by-step explanation:

đạo hàm cấp 2 của f(x) rồi thế 0 vào

Brian wants to buy the same
number of hats for 3 of his
friends. He has $57 dollars, and
each hat costs $5. What is the
greatest number of hats that
Brian buys for each friend?

Answers

3 hats each is the largest amount Brian can buy
To get this answer I multiplied 3 friends by $5 amount of each hat and got $15 then I divided that into 57$ and got 3.8. So he can only afford to get each friend 3 hats each Brian should have $12 left

Answer:each friend gets 3.

Step-by-step explanation:

Other Questions
Harn una lista de programas de televisin que puedan ayudarnos en algunos de nuestros cursos escolares I need help to Find the value of x. Round tothe nearest tenth. hi, please help me, solution. La lgalit quivaut l'exile.Discutez If you were exploring the topic of science education, what category of classical invention would it fall in Does this graph show a function? Explain how you know. Answer the following question Currently, nuclear energy provides only a small fraction (~10%) of energy used in the United States. In some other places, like France, it is close to 80%. Do you think nuclear energy will ever be a more widely used source of energy in the United States? Why or why not?PLEASE HELP ASAP PLEASEEE Who is the protagonist in this story?Select one:O a. Mr. Martino b. James ThurberO c. Mrs. BarrowsO d. Mr. Fitweiler measures that can unite all the ethnic groups in Ghana why is retting practiced with stem from Jute plant only and not with cotton When looking at the home page, where do you think you will find information about different kinds of bridges?a. Resourcesc. Build a bridgeb. Teacher's guided. None of the above ANSWER THIS FOR BRAINLIST PLS There are four main types of economic systems in use today.In a economy, people generally produce what they need to survive.A economy is a system in which resources and means of production are controlled by the government.In a economy, supply and demand dictate production, distribution, and investment decisions.Finally, a combination of market and command systems is found in a economy, in which free markets exist with some government intervention. For which of the following equations is x = 7 not a solution?4= -x + 11-3x = x - 28-5 = 2x 95x = 2x + 21 3. How fast can an impulse travel if the pathway is covered with myelin? Fo quality control purposes, we collect a sample of 300 items and find 36 defective items in it. Construct a 90% confidence interval [a, b] for the proportion of defective items in the whole shipment. Solve the equation -8(n + 7) = -88. What are two ways to start solving this equation? Choose BOTH ways.1) Subtract 7 from both sides.2) Use the distributive property.3) Add 8 to both sides.4) Add 88 to both sides.5) Divide both sides by -8. Which word best replaces the underlined phrase but keeps the original meaning of the sentence? the width of a rectangle is twice as long as the length. if the length is increased by 50% and the width is decreased by 20%, the perimeter becomes 248. find the width and length of the original rectangle.will give brainliest to correct answer The sum of three numbers is 78. The second number is 10 more than the first, and the third number is two times the second number.1. Write an equation that will help you determine the 3 numbers.2. Solve the equation showing all your steps.3. Tell what the 3 numbers are.