3) A sample of 42 grams of an unknown substance has a half-life of 1,300 years.

(a) Write an equation to determine the amount of substance, S, left after t years.

(b) Approximately how long will it take for 0.2 grams of substance to remain (to the nearest year)?

Answers

Answer 1

Answer:

a) [tex]S(t) = 42(0.9995)^t[/tex]

b) It will take 10,692 years.

Step-by-step explanation:

Exponential function to determine the amount of substance:

An exponential function to determine the amout of substance after t years is given by:

[tex]A(t) = A(0)(1-r)^{t}[/tex]

In which A(0) is the initial amount and r is the decay rate, as a decimal.

(a) Write an equation to determine the amount of substance, S, left after t years.

Half-life of 1300 years means that [tex]A(1300) = 0.5A(0)[/tex].

We use this to find r. So

[tex]A(t) = A(0)(1-r)^{t}[/tex]

[tex]0.5A(0) = A(0)(1-r)^{1300}[/tex]

[tex](1-r)^{1300} = 0.5[/tex]

[tex]\sqrt[1300]{(1-r)^{1300}} = \sqrt[1300]{0.5}[/tex]

[tex]1 - r = 0.9995[/tex]

[tex]r = 0.0005[/tex]

Sample of 42 grams means that [tex]A(0) = 42[/tex]. So

[tex]A(t) = A(0)(1-r)^{t}[/tex]

Replacing A by S, just for notation purposes

[tex]S(t) = 42(0.9995)^t[/tex]

(b) Approximately how long will it take for 0.2 grams of substance to remain (to the nearest year)?

This is t when [tex]S(t) = 0.2[/tex]. So

[tex]S(t) = 42(0.9995)^t[/tex]

[tex]0.2 = 42(0.9995)^t[/tex]

[tex](0.9995)^t = \frac{0.2}{42}[/tex]

[tex]\log{(0.9995)^t} = \log{\frac{0.2}{42}}[/tex]

[tex]t\log{0.9995} = \log{\frac{0.2}{42}}[/tex]

[tex]t = \frac{\log{\frac{0.2}{42}}}{\log{0.9995}}[/tex]

[tex]t = 10692[/tex]

It will take 10,692 years.


Related Questions

please solve the question below

Answers

Answer:

x = 5.61

Step-by-step explanation:

Applying the knowledge of similarity between two figures, thus:

Height of flag : height of Tommy = shadow length of flag : shadow o

Length of Tommy

30:5.5 = (25 + x) : x

30/5.5 = (25 + x)/x

30×x = 5.5(25 + x)

30x = 137.5 + 5.5x

30x - 5.5x = 137.5

24.5x = 137.5

x = 137.5/24.5

x = 5.61 (nearest hundredth)

divide 345609875by 13​

Answers

Answer:

26585375

Step-by-step explanation:

11.
8. The graph below shows the price Joanna
sells tomatoes according to their weight.
Write an equation for the graph.
h
H
Tomato Prices
12
10
Price (in dollars)
12
12.
Weight
(in pounds)
a. y = -x
6
10
b. y =
12
c.
=
d. y = x

Answers

Answer:

the question is invalid. please rewrite the question.

an enrollment of 200 students and this year enrollment has increased by 118%. What is this year's enrollment ?

Answers

Answer:

436 students

Step-by-step explanation:

Original number of students enrolled = 200students

% increase = 118%

Increment = 118% of 200

Increment = 1.18 * 200

Increment = 236

The year enrollment = 200 + 236

The year enrollment = 436 students

Find the distance between (6, 0) and (10, 3).
a 5 units
b 20 units
C 50 units
d None of the above


does anyone know this? geometry help pls

Answers

A 5 units I believe

Answer:

A

Algebra For what values of the variables must ABCD be a parallelogram?

B

23. A 2y + 2 B 24. B

(3x + 10)

(8x + 5)º

3x + 6

54°

D

С

D

A

Зу - 9 с

ly+4

Classify. * 6x^2 - 22x^5
a. quadratic binomial
b. quadratic polynomial
c. quintic binomial
d. not a polynomial ​

Answers

Answer:

Step-by-step explanation:

C

If x = t^3 and y = t^2 - 2 , what is y in terms of x?

Answers

Answer:

E

Step-by-step explanation:

You have to get t^2 in the first equation.

x = t^3                         Take the cube root of both sides

[tex]\sqrt[3]{x} = \sqrt[3]{t^3}[/tex]

[tex]\sqrt[3]{x}=t[/tex]                         Now square both sides

[tex](\sqrt[3]{x})^2 = t^2[/tex]

[tex]x^\frac{2}{3} = t^2[/tex]

Now you can substitute into the second equation

y = t^2 - 2

y = [tex]x^\frac{2}{3}[/tex] - 2

E

What is the slope of the line through (-4, 2) and (3, -3)? Choose 1 answer: (Α) 7 5 B 7 5 С 5 7 D 5 7​

Answers

Answer:

-5/7

Step-by-step explanation:

m=(y2-y1)/(x2-x1)

m=(-3-2)/(3-(-4))

m=-5/(3+4)

m=-5/7

Write an equation using “x” and then solve the equation. The rate charged for a standard room is $250 dollars. A couple stayed in a standard room for x nights and their total room charge is $750.

Answers

Answer:

3 nights

Step-by-step explanation:

total charge = rate times time interval

Here, time interval = total charge / rate

                               $750 = ($250/night)(n nights)

                                Solving for n, we get n = 3 (nights)

An equation for a couple stayed in a standard room for x nights and their total room charge is $750 is, 250x  = 750

What is an Equation ?

An equation is a mathematical term, which indicates that the value of two algebraic expressions are equal. There are various parts of an equation which are, coefficients, variables, constants, terms, operators, expressions, and equal to sign.

For example, 3x+2y=0.

Types of equation

1. Linear Equation

2. Quadratic Equation

3. Cubic Equation

Given that,

The rate charged for a standard room is $250 dollars

A couple stayed in a standard room for x nights

Total room charge =  $750

Equation = ?

Total charge = 250 × x

Total charge =  750

So,

250x  = 750

Thus, an equation is 250x  = 750

To know more about Equation check:

https://brainly.com/question/1529522

#SPJ2

Evaluate the limit(-2n^n/4+n

Answers

Answer:

.

Step-by-step explanation:

Answer: 4/8 equals 4/89

Find the slop of the line given y - 1 = -5(x + 19)

Answers

Answer:

m = − 5 is slope

Step-by-step explanation:

which function displays the fastest growth as the x-values continue to increase?

Answers

D. q(x)
it is the only exponential function
y is multiplied by 2 each time c increases by 1

The exponential function q(x) displays the fastest growth as the x-values continue to increase.

The correct option is D.

What is an exponential function?

Mathematical functions with exponents include exponential functions. f(x) = bˣ, where b > 0 and b 1, is a fundamental exponential function.

Given:

A table is given for the value of x.

The function m(x) shows the linear relationship.

Because it has constant first difference.

n(x) is not a function because it has 2 input values connecting to one output value.

And the function q(x) has common ratio,

0.3/0.15 = 2.

So, it is an exponential function.

So, this function will display the fastest growth.

Therefore, the function is q(x).

To learn more about the exponential;

https://brainly.com/question/14344314

#SPJ6

What is 288/-32 in its standard form

Answers

Answer:

[tex] \frac{288}{ - 32} = \frac{ - 9}{1} \\ = - 9[/tex]

Answer:

the simplest form of 288/-32 is 91.

Step-by-step explanation:

hope this helps sorry if im wrong

What number is between 5/2 and the other number In the photo.

Answers

5/2 would simplify to 2.5 and √11 would be 3.3 so the answer should be 3

Please please give answer for this question

Answers

Answer:

The remaining piece measures 16 m

which agrees with answer D

Step-by-step explanation:

In order to make a square of area 25 m^2, we need a square of side 5 m ,

Area of square = side^2

25 = side^2   then each side = 5 m

therefore the person needed 4 times 5 m  to create the square, that is 20 m for the square. Therefore the piece that is left can be calculated with the difference:

36 m - 20 m = 16 m

The remaining piece measures 16 m

The length of a rectangle multiplied by 3 is equal to 4 times its width. The perimeter is 8 2/5 feet. Find the length and width.

Answers

Answer:

W=1 4/5 feet

L= 2 2/5 feet

Step-by-step explanation:

3L = 4W     L = 4W/3

2L+2W = 8 2/5

Substitute L

2(4W/3)+2W = 8 2/5

8W/3+2W = 8 2/5

multiply both sides by 3

8W+6W = 24 6/5

14W = 25 1/5

Divide both sides by 14

14W/14 = (25 1/5)/14

W = (126/5)/14 = 9/5 = 1 4/5

Substitute for W

L = 4(1 4/5)/3

L = (4)(9/5)/3 = (36/5)/3 = 12/5 = 2 2/5

The perimeter is an enclosed area of any two or one-dimensional shape.

The perimeter of a rectangle is given by:

[tex]\rm P = 2 ( L + B )[/tex]

The length is [tex]\rm 2 \dfrac{2}{5} feet[/tex] and the width of the rectangle is [tex]\rm 1\dfrac{4}{5} feet[/tex].

This can be calculated by:

Given,

Perimeter (P) = [tex]\rm 8 \dfrac{2}{5} feet[/tex]

Let,

Length = L

Width = W

Since,

3L = 4W

[tex]\rm L = \dfrac{4W}{3}[/tex]

Substituting the value of L in the equation of perimeter:

[tex]\rm 2(\dfrac{4W}{3}) + 2W = 8 \dfrac{2}{5}[/tex]

[tex]\rm \dfrac{8W}{3} + 2W = 8 \dfrac{2}{5}[/tex]

Now multiplying the left and right sides by 3 we get:

[tex]\rm 8W+6W = 24 \dfrac{6}{5}[/tex]

[tex]\rm 14W = 25 \dfrac{1}{5}[/tex]

Now divide both sides by 14:

[tex]\rm \dfrac{14W}{14} =\dfrac{(25 \dfrac{1}{5})}{14}[/tex]

[tex]\rm W = \dfrac{(\dfrac{126}{5})}{14} \\\\= \dfrac{9}{5}[/tex]

[tex]\rm W = 1 \dfrac{4}{5}[/tex]

Now substituting the value of W, length can be calculated:

[tex]\rm L = \dfrac{4(1 \dfrac{4}{5})}{3}[/tex]

[tex]\rm L = \dfrac{(4)\dfrac{9}{5}}{3} \\\\= \dfrac{(\dfrac{36}{5})}{3} \\\\= \dfrac{12}{5}[/tex]

[tex]\rm L = 2 \dfrac{2}{5}[/tex]

Therefore, length is  [tex]\rm 2 \dfrac{2}{5} feet[/tex]  and width is [tex]\rm 1\dfrac{4}{5} feet[/tex].

To learn more about the perimeter of rectangle follow the link:

https://brainly.com/question/8966512

Simplify (4x^2y)(3xy)(2xy)^3
A. 96x^4y^5
B. 96x^6y^5
C. 24x^4y^5
D. 24x^6y^5

Answers

Answer:

the answer is D

Step-by-step explanation:

hard to explain it with just words and not be able to show you step by step

Two different age groups were surveyed about the amount of time they spent on social media.

Answers

What’s the question-

For b you had to add 25 and 35 together to make 60.

Divide 60 by 2 to get 30. 30 is the average between the two numbers. You then find the frequency of 30 using the graph. For the 12 year olds it is 40 and for the 18 year olds it is 60. Find the difference between these 2. So 60-40= 20


An airline charges $462.40 for all the passengers on the plane to have pretzels. Each
bag of pretzels is $3.40. How many passengers are on the plane?

Plz help ty

Answers

Answer:

136 people

Step-by-step explanation:

$462.40 divided by 3.40 is 136

On a trip, a family travels 180 km in 2.5 h on the first day, 220 km in 4.4 h on the second day, and 88 km in 2.2 h on the third day. What was the average speed, in kilometers per hour, for the total trip?

Answers

Answer:

Step-by-step explanation:

180+220+88 = 488 km

2.5+4.4+2.2 = 9.1 h

(488 km )/(9.1 h) = (488/9.1 km)/h ≈ 53.6 km per hour

20 PTS !!!!!!
HELP PLEASE

Answers

It is 53...... BODMAS

Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell five cars; nineteen generally sell six cars; twelve generally sell seven cars; nine generally sell eight cars; eleven generally sell nine cars. Calculate the following. (Round your answer to two decimal places.)Data Value (# cars) Frequency Relative Frequency Cumulative Relative Frequency

Answers

Answer:

Step-by-step explanation:

From the information given:

We can compute the required calculations into a table as shown below.

[tex]\mathbf{Data \ value }[/tex]       [tex]\mathbf{ Frequency }[/tex] [tex]\mathbf{Relative \ frequency}[/tex]   [tex]\mathbf{Cumulative \ relative }[/tex]

                                                                                              [tex]\mathbf{Frequency}[/tex]

5                                     14                14/65 = 0.22                           14  

6                                     19                19/65 = 0.29               19+14 = 33

7                                      12                12/65 = 0.19               33+12 = 45

8                                       9                 9/65 = 0.14               45 + 9 = 54

9                                     11                11/65  = 0.17              54 + 11 = 65

                                        65

Note: that the relative frequency is determined by  dividing each value in the frequency by the total of the frequency.                        

Pls help extra points and mark brainlist

Answers

Answer:

the answers are a and d

Step-by-step explanation:

x+x+x=3x and you can't add a constant (2) to a variable(3x) so it would just be 3x+2

Which of the following is not a characteristic of both experiments and
surveys?
A. The researcher exercises direct control over at least one variable.
B. Subjects should be randomly selected.
C. Data are collected about a population.
D. The data collected might be studied for patterns.

Answers

The researcher exercise direct control over at least one variable.

Answer:

C?correct me if I'm wrong

Please help with work and explanation

Answers

y = 135 . your welcome

In a carnival game, there are six identical boxes, one of which contains a prize. A contestant wins the prize by selecting the box containing it. Before each game, the old prize is removed and another prize is placed at random in one of the six boxes. Is it appropriate to use the binomial probability distribution to find the probability that a contestant who plays the game five times wins exactly twice

Answers

Answer:

The probability that a contestant who plays the game five times wins exactly twice is [tex]16.08[/tex] %

Step-by-step explanation:

We will use binomial theorem here

[tex]C_{n,k}p^k(p')^{n-k}[/tex]

Substituting the available values in above equation, we get

[tex]C_{5,2} * \frac{1}{6}^2*\frac{5}{6}^3[/tex]

[tex]0.1608[/tex]

OR

The probability that a contestant who plays the game five times wins exactly twice is [tex]16.08[/tex] %

Is x-6 a factor of 3x^3-16x^2-72?

Answers

Answer:

No

Step-by-step explanation:

its not because x doesn't go into all 3 coffecients (numbers) and 6 doesn't go into 3.

Answer:

no because x dosent go into all 3 coefficents (numbers) and 6 dosent go into 3

Step-by-step explanation:

answer plz plz for brainleiest

Answers

Answer:

-.5

Step-by-step explanation:

Answer:

B=0.5 or 1/2

its correct please give brainliest!!!

operación 1: (6+(4*12)/12-2)+5​

Answers

Answer:

13

Step-by-step explanation:

6+ (4)(12) /12 −2+5

=6+ 48 /12 −2+5

=6+4−2+5

=10−2+5

=8+5

=13

cual es la longitud del alambre que sostiene un poste de 8 m de altura , si dicho alambre esta amarrado al suelo a 4m del poste​

Answers

Answer:

La longitud del alambre que sostiene el poste es 8.94 metros.

Step-by-step explanation:

La longitud del alambre se puede calcular usando Pitágoras:

[tex] L^{2} = P^{2} + B^{2} [/tex]                      

En donde:

L: es la longitud del alambre =?

P: es la altura del poste = 8 m

B: es la distancia del alambre al poste = 4 m

Entonces, la longitud del alambre es:

[tex] L = \sqrt{P^{2} + B^{2}} = \sqrt{(8 m)^{2} + (4 m)^{2}} = 8.94 m [/tex]  

Por lo tanto, la longitud del alambre que sostiene el poste es 8.94 metros.

                               

Espero que te sea de utilidad!

Other Questions
2/5 of 146 as a decimals - Importaciones $ 148.000.- Exportaciones $ 120.000.-Saldo de la Balanza comercial Positivo o negativo? Pas rico o pobre - Por qu? Which graph shows u + v for the given vectors u and v? BRAINLIEST AND 30 POINTSGeorge Stephenson was a British inventor and engineer who designed many of the first railroad tracks. How did Stephenson's work contribute to the success of the railroad system?A. He build his tracks using a type of steel that would last a long time because of the proportion of iron in the rails.B. He designed a type of track that could be curved around obstacles more easily.C. He insisted that all of the tracks he designed conformed to a standard size, which made it easier to connect all the tracks later.D. He worked with locomotive designers to ensure the the trains would run smoothly on his tracks The principal enzyme involved in DNA replication is called . The enzyme joins to synthesize a new strand of DNA . DNA replication is called , because each new DNA molecule is made up of one original and one new strand. who is first President of indiaa)Rajendra Prasadb)Sarvepalli Radhakrishnanc)Vallabhbhai Patel The Milky Way galaxy was given its name because of what it looks like when viewed from Earth. True False A table is 2 feet wide. It is 6 times as long as it is wide. 6 (8j - 3l + 9 ) 12l + 14j solve for x or find x Who was Zheng He, and what did he do? Which phrase describes runoff?1.underground water that flows into lakes2.river water that empties into an ocean3.water from streams that flows into larger rivers4.water from rain and snow that travels to streams Please help! can you help me with this? plz i am very tired Vinny and Sandra have just had their first baby, and need to make a decision about how to handle work and childcare responsibilities. Vinny earns $1000 per week working full time, and Sandra's fulltime salary is $1200 per week. They each can work part time and earn half their fulltime wage. Calculate the change in GDP for each situation, relative to when they both worked full time and had no childcare responsibilities. If GDP falls, include a negative sign in your answer. a. Both Vinny and Sandra return to work full time and pay a childcare provider $600 per week to care for their child. $ b. Both Vinny and Sandra will return to work full time, while Sandras mother takes care of their child without financial compensation. $ c. Both Vinny and Sandra will return to work full time, while Vinny's brother takes care of their baby. They'll pay him $600 a week to care for their child, but neither they nor Vinnys brother will report those payments to the IRS, or on any government surveys. $ d. Vinny and Sandra will each return to work part time, and split childcare responsibilities. $ e. Vinny will stay home to care for the baby, while Sandra returns to work full time. $ Which do the following options represent the measure of arc RAA.38.6B.65.6C.71.4D.77.2 Na on the periodic table is the symbol for what? Stem-Changing ("Boot") Verbs/ Verbos con cambios radicalesThere are three main typesof stem-changing verbs in the present tense:andWhen we say verbs have "stem-changes we mean that part of the infinitivechanges. Thevowel in the infinitive changes in everyandforms.form of the verb BUT theStem-changing verbs are also known as __bost VectsPrctica: First, underline or circle which vowel in the following verbs changes. The stem changesare already given to you. Then, conjugate four of the verbs (one of each kind) in the space below.O>UEEIEEIPoderTo be able toQuerer = To wantServir = To servePreferir = To preferMedir = To measure Jugar" = To playPedir - to ask for!order Dormir = To sleepVenir" = To comeVerbo: Querer-Verbo: poderVerbo: pedir:Verbo: jugar What is the answer Please help me Circle D is shown. Line segment F E goes through point D. Line segment C D is shown. Line segment G H goes from one side of the circle to the other side. Line segment A B is outside of the circle and intersects the circle at point B.In circle D, which is a secant?EFDCLine segment A BLine G H 3. A recommendationa. is written after the researcher has drawn conclusions.b. is based on the findings of the research.c. suggests specific interventions or strategies to address the issues at hand.d. all of the above