The half-life of a radioactive substance is the time required for half of a sample to undergo radioactive decay, or for the quantity to fall to half its original amount. Carbon 14 has a half-life of 5,730 years. Suppose given samples of carbon 14 weigh (fraction 5/8) of a pound and (fraction 7/8) of a pound. What was the total weight of the samples 11460 years ago
(show work please)

Answers

Answer 1
That's two half lives. 5/8 * 2 * 2 = 20/8 = 5/2 pounds7/8 * 2 * 2 = 28/8 = 7/2 pounds
Answer 2

Answer:

Amount of C-14 taken were 2.5 pounds and 3.5 pounds respectively.

Step-by-step explanation:

Radioactive decay is an exponential process represented by

[tex]A_{t}=A_{0}e^{-kt}[/tex]

where [tex]A_{t}[/tex] = Amount of the radioactive element after t years

[tex]A_{0}[/tex] = Initial amount

k = Decay constant

t = time in years

Half life period of Carbon-14 is 5730 years.

[tex]\frac{A_{0} }{2}=A_{0}e^{-5730k}[/tex]

[tex]\frac{1}{2}=e^{-5730k}[/tex]

Now we take ln (Natural log) on both the sides

[tex]ln(\frac{1}{2})=ln[e^{-5730k}][/tex]

-ln(2) = -5730kln(e)

0.69315 = 5730k

[tex]k=\frac{0.69315}{5730}[/tex]

[tex]k=1.21\times 10^{-4}[/tex]

Now we have to calculate the weight of samples of C-14 taken for the remaining quantities [tex]\frac{5}{8}[/tex] and [tex]\frac{7}{8}[/tex] of a pound.

[tex]\frac{5}{8}=A_{0}e^{(-1.21\times 10^{-4}\times 11460)}[/tex]

[tex]\frac{5}{8}=A_{0}e^{(-1.21\times 10^{-4}\times 11460)}[/tex]

[tex]\frac{5}{8}=A_{0}e^{(-1.3863)}[/tex]

[tex]A_{0}=\frac{5}{8}\times e^{1.3863}[/tex]

[tex]A_{0}=\frac{5}{8}\times 4[/tex]

[tex]A_{0}=\frac{5}{2}[/tex]

[tex]A_{0}=2.5[/tex] pounds

Similarly for [tex]\frac{7}{8}[/tex] pounds

[tex]\frac{7}{8}=A_{0}e^{(-1.21\times 10^{-4}\times 11460)}[/tex]

[tex]\frac{7}{8}=A_{0}e^{(-1.21\times 10^{-4}\times 11460)}[/tex]

[tex]\frac{7}{8}=A_{0}e^{(-1.3863)}[/tex]

[tex]A_{0}=\frac{7}{8}\times e^{(1.3863)}[/tex]

[tex]A_{0}=\frac{7}{8}\times 4[/tex]

[tex]A_{0}=\frac{7}{2}[/tex]

[tex]A_{0}=3.5[/tex] pounds


Related Questions

Sketch each parabola using the given information.

vertex (3, 6), y-intercept 2

Answers

put a point at (3,6)
put a point at (0,2)
hmm
parabola, so it is same on left and right
so from (3,6) to (0,2) is 3 down and 4 left
so we do the oposite in the other direction (left to right flip)
frmo (3,6), go 3 down and 4 right
get (3,10)
graph that pont as well

graph points (3,6) and (0,2) and (3,10)
(just fyi, the equaton is y=(-4/9)(x-3)^2+6)

a dragongfly traveled at a rate of 35 miles per hour for 2.5 hours .what distance did the dragonfly travel?

Answers

We Know, Distance = Speed * Time

Here, Speed = 35 mi/hr
Time = 2.5 hr

Substitute their values into the expression,
Distance = 35 * 2.5 = 87.5

So, your final answer is 87.5 miles

Hope this helps!

If the price of an item is $34 and the sales tax on it is $1.36, what is the sales-tax rate? You can use the calculator tool.

Answers

Answer:

$0.04 per $1

Step-by-step explanation:

If you pay $1.36 for $34, then the tax rate is 1.36/34=0.04

That's for each dollar value of an item, you pay $0.04

The length of a rectangle is 3 meters more than twice its width. the length of this rectangle is 10 meters. write an equation to solve the perimeter of this rectangle

Answers

I hope this helps you

How many grams are in 40 hectograms

Answers

there are 4000, hope this helps. :)

There are 4000 grams in 40 hectograms.

To convert from hectograms to grams, you need to know that there are 100 grams in 1 hectogram.

Therefore, to find out how many grams are in 40 hectograms, you can use the conversion factor:

40 hectograms * 100 grams/hectogram = 4000 grams

So, there are 4000 grams in 40 hectograms.

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PLEASE HELP BEGGGING YOU
the point Q(9,-1) is reflected across the y axis. Use arrow notation to describe the original point and its reflection

Q(9,-1)----Q(9,1)
Q(9,-1)----Q (-9,1)
Q(9,-1) ------Q(-9,-1)
Q(9,-1) ----Q(9,-1)

Answers

Answer:

C is the answer.

Step-by-step explanation:

When you reflect over the y-axis, the y-axis will remain the same and the x-axis will change from either positive to negative, or negative to positive in this case it is positive to negative.

Use the substitution method to solve the system of equations. 2x - y = 10 3x - 2y = 8

Answers

2x-y=10
3x-2y=8

-y= -2x +10 multiply by(-1)
y=2x-10

3x-2(2x-10)=8
3x-4x+20=8
-x=-12 multply by (-1)
x=12
24-y =10
-y=-14
(12,14)

Answer:

x=12, y=14

Step-by-step explanation:

[tex]2x - y = 10[/tex]

Solve the equation for y. Subtract 2x from both sides

[tex]- y = -2x+10[/tex]

Divide both sides by -1

[tex]y=2x-10[/tex]

Substitute 2x-10 for y in the second equation

[tex]3x - 2(2x-10)= 8[/tex]

[tex]3x - 4x+20= 8[/tex]

[tex]-1x+20= 8[/tex]

Subtract 20 from both sides

[tex]-1x= -12[/tex]

Divide both sides by -1

x= 12

[tex]y=2x-10[/tex]

Substitute 12 for x

[tex]y=2(12)-10=14[/tex]

y=14

square root of 85 is between what two consecutive number

Answers

   
[tex]\sqrt{81} \ \textless \ \sqrt{85} \ \textless \ \sqrt{100} \\ \\ \boxed{9 \ \textless \ \sqrt{85} \ \textless \ 10 } \\ \\ [/tex]




4x + 5x + 12 = -6 (given)
9x + 12 = -6 (simplify)
9x = -18 (subtraction)
x = -2 (addition)

Which reason is incorrect?
A) addition
B) given
C) simplify
D) subtraction

Answers

The last step is incorrect. Addition is NOT used. Instead, division is used since both sides were divided by 9

So the answer is choice A) addition. 

Answer:

Addition

Step-by-step explanation:

USA Testprep

if the point (x, –1) is on the unit circle, what is the value of x?

Answers

The value of x will be 0

Answer:

0^2 (–1)2 = 1.

Step-by-step explanation:

In the diagram below, BC is an altitude of ABD. To the nearest whole unit, what is the length of CD?

Answers

Answer:

Actually the answer is 56, so D.

Step-by-step explanation:


To the nearest whole unit, the length of CD is approximately 4 units.

Given Information:

In triangle ABD, BC is an altitude (perpendicular) from point B to side AD.

We need to find the length of CD.

Approach:

Since BC is an altitude, triangle BCD is a right triangle with BC as one of its legs and BD as its hypotenuse.

We can use the Pythagorean theorem to relate the lengths of BC, CD, and BD.

Pythagorean Theorem: The Pythagorean theorem states that in a right triangle:[tex][ \text{Hypotenuse}^2 = \text{Leg}_1^2 + \text{Leg}_2^2 ][/tex]

Application to Triangle BCD:

Let’s denote the length of CD as (x).

BC is given as 30 units.

BD can be expressed as (BD = AB + AD), where AB is the length of the other leg.

Using Triangle ABC:

Triangle ABC is also a right triangle.

We have AC = 16 units (given).

Using the Pythagorean theorem for triangle ABC: [tex][ AB^2 + BC^2 = AC^2 \ AB^2 + 30^2 = 16^2 \ AB^2 + 900 = 256 \ AB^2 = 256 - 900 \ AB^2 = -644 ][/tex]

Since we cannot have a negative side length, we discard this solution.

Using Similar Triangles:

Notice that triangle BCD is mathematically similar to triangle ACE.

The coefficient of similarity is evident from the side CE.

We can set up the following proportion: [tex][ \frac{BC}{CD} = \frac{AC}{CE} \ \frac{30}{x} = \frac{16}{CE} \ CE = \frac{16x}{30} ][/tex]

Finding BD:

We know that (BD = AB + AD).

Since we couldn’t find AB directly, we express it in terms of CE:[tex][ AB = AC - CE = 16 - \frac{16x}{30} = \frac{480 - 16x}{30} ][/tex]

Now, we can find BD: [tex][ BD = AB + AD = \frac{480 - 16x}{30} + 16 = \frac{480 + 480 - 16x}{30} = \frac{960 - 16x}{30} ][/tex]

Applying the Pythagorean Theorem to Triangle BCD: [tex][ BD^2 = BC^2 + CD^2 \ \left(\frac{960 - 16x}{30}\right)^2 = 30^2 + x^2 \ 960^2 - 32x \cdot 960 + 256x^2 = 900x^2 + 900 \cdot 30^2 \ 960^2 - 32x \cdot 960 = 900x^2 - 900 \cdot 30^2 \ 960^2 + 900 \cdot 30^2 = 932x^2 \ x^2 = \frac{960^2 + 900 \cdot 30^2}{932} \ x \approx 3.75 ][/tex]

To the nearest whole unit, the length of CD is approximately 4 units.

the ordered pair for an x-intercept has an x-value of 0 A.True or False

Answers

False
You question basically is saying- (0,a number) 
If we wanted the x intercept it would have to be (a number,0)  

The ordered pair for an x-intercept has an x-value of 0 has some value of x and it has zero value for y, So it is a False statement.

What is the equation of line?

The equation of a straight line is a relationship between x and y coordinates, The general equation of a straight line is y = mx + c, where m is the slope of the line and c is the y-intercept.

Given statement,

the ordered pair for an x-intercept has an x-value of 0

we can see in graph that when line intersect the x axis, the x coordinate of that point is known as x-intercept,

suppose, we have one line , y = 3x+3

so when we draw graph for it,

and if we see x-intercept

it will come out as,   0 = 3x+3 ⇒ x = -1

It is clear that value of x is not zero

hence, the given statement is false

To know more about Line check:

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Imaginary Numbers
Simplify
i^9

Answers

i = √-1
This means that i^2 = -1
If you square i until the 9th power, you will realize that i^9 = 1, or simply i.
So, your answer is i^9 = i. 

Answer:

i^9 = i

Step-by-step explanation:

36% of what number is 180?

Answers

let the number be x
36% of x = 180
36/100×x=180
x=(180×100)/36
x=500

**^^**
While doing a math problem in class, Jared's answer was different from his teacher's. So she had him come up and work the problem on the board. Here's Jared's work.

36.47
x 12
----------
7294
+ 3647
-----------
109.41

What was his mistake?

A>He multiplied incorrectly.
B>He left out the place holder under the 4.
C>There are not enough numbers after the decimal.
D>The sum of 7,294 and 3,647 is incorrect.

Answers

Answer:

The other answer is wrong, actually

Step-by-step explanation:

The real answer is B, He left out the place holder under the 4.

Jared did not multiply incorrectly.

What is 2x-16=90 in Algebra1

Answers

In order to get x, you would get rid of everything else around it. -16 is the last thing you did to form this equation, so you would add 16 to both sides, which would get you 2x = 106. Since you want x by itself, you would divide 2 on both sides, which would get you x = 53. And the answer would be x = 53.
x = 53.

90 + 16 = 106, then you divide by 2 to find x, and x equals 53.

step 1: add 16 to 90.

90 + 16= 106..

step 2: divide both side by 2. 

106/2 = 53. 2x/2 would cancel out.

x= 53, and this is how you would solve to find x.










What is the domain of the quadratic function graphed below?

Answers

I would have to see the graph.

what is 3/20 as a decimal equivalent

Answers

3/20 as a decimal equivalent is 0.15
The equivalent decimal is 0.15

A donut shop is experimenting with two new types of cream-filled treats, one with raspberry filling, and the other with peach. A batch of raspberry donuts cooks in 11 minutes while a batch of peach donuts cooks in only 8 minutes.
Let x represent the number of raspberry-filled donuts and let y represent the number of peach-filled donuts. Write an inequality to represent how many batches of the new type of donuts can be produced in a 10 hour day.

Answers

I turned hours into minutes (10hrs = 600mins)

11x < or = 600
8y < or = 600

or combine them:
11x + 8y < or = 600

Answer:

The required inequality is [tex]11x + 8y \leq 600[/tex]

Step-by-step explanation:

Given : A donut shop is experimenting with two new types of cream-filled treats, one with raspberry filling, and the other with peach.

A batch of raspberry donuts cooks in 11 minutes while a batch of peach donuts cooks in only 8 minutes.  

Let x represent the number of raspberry-filled donuts and let y represent the number of peach-filled donuts.

To write : An inequality to represent how many batches of the new type of donuts can be produced in a 10 hour day.

Solution :

Time taken to cook the raspberry donuts = [tex]11x[/tex] minutes

Time taken to cook the peach donuts = [tex]8y[/tex] minutes

Donuts produced in 10 hours

1 hours = 60 minutes

10 hours = 60 × 10 = 600 minutes

Total time ≤ 600 minutes

Therefore, the required equation is

→ [tex]11x + 8y \leq 600[/tex]



Brandon can paint a fence in 12 hours and Elaine can paint the same fence in 11 hours. How long will they take to paint the fence if they work together?
A) 5 13/24 hr
B) 5 ¾ hr
C) 11 ½ hr
D) 5 17/23 hr

Answers

C) 11 ½ hr 
12/2 + 11/2 = 11.5

Answer:5 17/23

Step-by-step explanation:

7x-5y=4; what does x and y equal

Answers

To solve for x:

7x - 5y = 4   Add 5y to both sides
       7x = 5y + 4   Divide both sides by 7
         x = [tex] \frac{5}{7} [/tex]y + [tex] \frac{4}{7} [/tex]
                 or
         x = [tex] \frac{5y + 4}{7} [/tex]

To solve for y:

7x - 5y = 4   Subtract 7x from both sides
      -5y = -7x + 4   Divide both sides by -5
         y = [tex] \frac{7}{5} [/tex]x - [tex] \frac{4}{5} [/tex]
                or
         y = [tex] \frac{7x - 4}{5} [/tex]

Camille Keegan sells lamps for $105.55 that cost her $75.00. Camille's percent of markup based on the selling price is:

Answers

Markup = $105.55 - $75 = $30.55. Percentage markup based on selling price = $30.55 / $105.55 * 100% = 28.94%

Final answer:

Camille's percent of markup based on the selling price is calculated by finding the difference between the selling price and the cost price, dividing by the selling price, and then multiplying by 100. The calculation reveals that the markup percentage is approximately 28.94%.

Explanation:

The question asks us to calculate Camille Keegan's percentage of markup based on the selling price of the lamps. The markup is the difference between the selling price and the cost price. To find the percentage of markup based on the selling price, we use the formula: (Markup / Selling Price) × 100. First, we find the markup by subtracting the cost price from the selling price, which is $105.55 - $75.00 = $30.55. Then we divide the markup by the selling price: $30.55 / $105.55. Finally, we multiply the result by 100 to get the percentage of markup based on the selling price.


Step-by-step calculation:

Markup = Selling Price - Cost Price = $105.55 - $75.00 = $30.55Percentage of Markup = (Markup / Selling Price) × 100Percentage of Markup based on the Selling Price = ($30.55 / $105.55) × 100 ≈ 28.94%


Therefore, Camille's percent of markup based on the selling price of the lamps is approximately 28.94%.

each month for 7 months, samuel mows 3 lawns. how many more lawns does he need to mow before he has mowed 29 lawns?

Answers

He needs to mow 6 more lawns

The seats at a local baseball stadium are arranged so that each row has five more seats than the row in front of it. If there are four seats in the first row, how many total seats are in the first 24 rows?

These are the choices
1,476
2,856
2,952
1,428 ...?

Answers

numbers of seats in a row makes an arithmetic series chairs in the nth row an = 4 + 23*5 = 119 and the sum is sn = (4 + 119) * 24/2 = 1476

One number is 3 less than twice another. If their sum is 39, find the numbers.
Which of the following systems of equations represents the word problem?
A.y = 2x - 3 and y = x + 39
B.y = 2x - 3 and x + y = 39
C.y = 2(x - 3) and x + y = 39 ...?

Answers

B.y = 2x - 3 and x + y = 39

Let

y------> one number

x-----> another number

we know that

[tex]y=2x-3[/tex] ------> equation A

[tex]x+y=39[/tex] ------> equation B

substitute equation A in equation B

[tex]x+[2x-3]=39[/tex]

[tex]3x=39+3[/tex]

[tex]x=42/3=14[/tex]

Find the value of y

[tex]y=2*14-3=25[/tex]

the numbers are [tex]25[/tex] and [tex]14[/tex]

therefore

the answer is the option B

[tex]y=2x-3[/tex] and [tex]x+y=39[/tex]

Can a cubic equation have 3 complex roots? 3 real roots? ...?

Answers

No, a cubic equation can not have three complex roots. This is because it turns twice and one end goes to positive infinity and one end goes to negative infinity. Thus, one of these MUST cross the x-axis at some point, meaning y = 0 and a real root exists.

Yes, a cubic equation can have three real roots if it cuts the x-axis three times.

Final answer:

A cubic equation can have either three real or three complex roots (including a real root and a pair of complex conjugate roots), determined by its discriminant. Complex roots arise in pairs due to the conjugate root theorem, ensuring that the coefficients of the equation remain real.

Explanation:

A cubic equation, which is an equation of the form ax^3 + bx^2 + cx + d = 0, can indeed have 3 complex roots or 3 real roots, depending on the discriminant and the nature of the coefficients. According to the Fundamental Theorem of Algebra, every cubic equation has three roots in the complex number system, which includes real numbers as a subset.

If the discriminant is positive, the cubic equation has three distinct real roots. If the discriminant is zero, the equation has a multiple root and all its roots are real.

Equilibrium problems in mathematics may require using cube roots when finding the solution, and utilizing the correct functions on a calculator is vital for these calculations. This could be in applied sciences like chemistry or physics, where cubic equations may arise.

$800,000 if your rate of return is 5.3% compounded monthly
If you deposit the amount you need to achieve your goal in 20 years, how much will your savings be worth after 10 years?

Answers

30 years so if you have anymore questions then just feel free to ask them i will answer all of them so go ask me a question down below.

Eric sells shirts. It costs him $100 to buy all the shirts and $10 to print designs on the shirts. Eric sells each shirt for $4. So far Eric has sold 20 shirts. Eric uses an equation to calculate his total profit.

What is the slope of the equation modeling this situation?

Answers

Y= 4(100+10) Because the slope is the total cost it is to make the shirts times what you made from the cost ($4)

To find the slope of the equation modeling Eric's situation, subtract the total cost from the selling price per shirt, resulting in a loss of $106 per shirt sold.

The slope of the equation modeling Eric's situation can be calculated as follows:

Profit per shirt = Selling price per shirt - Total cost per shirtProfit per shirt = $4 - ($100 + $10)Profit per shirt = $4 - $110 = -$106

The slope, which represents the profit per shirt, is -$106, indicating a loss of $106 for each shirt sold.

Rewrite with only sin x and cos x.

cos 3x


cos x - 4 cos x sin2x

-sin3x + 2 sin x cos x

-sin2x + 2 sin x cos x

2 sin2x cos x - 2 sin x cos x

Answers

this may help you, check the attached file

Final answer:

To rewrite expressions using only sin x and cos x, we can use trigonometric identities like [tex]cos 2x = 1 - 2sin^2 x[/tex] and sin 2x = 2sin x cos x. By applying these identities, we can simplify the given expressions.

Explanation:

To rewrite the given expressions using only sin x and cos x, we can use the following trigonometric identities:

[tex]cos 2x = 1 - 2sin^2 x[/tex]sin 2x = 2sin x cos x[tex]sin 3x = 3sin x - 4sin^3 x[/tex]

Using these identities, we can rewrite the expressions as follows:

cos 3x = [tex]4cos^3 x - 3cos x[/tex]cos x - 4cos x sin^2 x = cos x - 4sin x cos x sin x = [tex]cos x - 4sin^3 x cos x[/tex]-sin 3x + 2sin x cos x = [tex]-(4sin^3 x) + 2sin x cos x[/tex] = [tex]-4sin^3 x + 2sin x cos x[/tex]-sin 2x + 2sin x cos x = -2sin x cos x + 2sin x cos x = 0[tex]2sin^2 x cos x - 2sin x cos x[/tex] = 2sin x cos x (sin x - 1)

Gina works at a diner. She earns $6 each hour plus tips.In one week,she worked 37 hours a week and earned $43 in tips.How much did she make altogether? Write an equation. Use a variable for the unknown.Solve.

Answers

The answer is $265 (how much did she make altogether)

The equation is x=6h+6


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