A sample of a radioactive isotope had an initial mass of 360 mg in the year 1998 and
decays exponentially over time. A measurement in the year 2004 found that the
sample's mass had decayed to 270 mg. What would be the expected mass of the
sample in the year 2011, to the nearest whole number?

Answers

Answer 1

Answer:

193 mg

Step-by-step explanation:

Exponential decay formula:

[tex]A_t = A_0e^r^t[/tex]where Aₜ = mass at time t, A₀ = mass at time 0,  r = decay constant (rate), t = time  

Our known variables are:

1998 to the year 2004 is a total of t = 6 years.The sample of radioactive isotope has an initial mass of A₀ = 360 mg at time 0 and a mass of Aₜ = 270 mg at time t.

Let's solve for the decay constant of this sample.

[tex]270=360e^-^r^(^6^)[/tex][tex]270=360e^-^6^r[/tex] [tex]\frac{3}{4} =e^-^6^r[/tex][tex]\text{ln} (\frac{3}{4} )= \text{ln}(e^-^6^r)[/tex] [tex]\text{ln} (\frac{3}{4} )=-6r[/tex] [tex]r=-\frac{\text{ln}\frac{3}{4} }{6}[/tex] [tex]r=0.04794701[/tex]

Using our new variables, we can now solve for Aₜ at t = 7 years, since we go from 2004 to 2011.

Our new initial mass is A₀ = 270 mg. We solved for the decay constant, r = 0.04794701.

[tex]A_t=270e^-^(^0^.^0^4^7^9^4^8^0^1^)^(^7^)[/tex] [tex]A_t=270e^-^0^.^3^3^5^6^2^9^0^7[/tex][tex]A_t=193.01982213[/tex]

The expected mass of the sample in the year 2011 would be 193 mg.


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for the equation below y=2.5^x-6

what is the y intercept of the graph

a) -6
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Answer:

kvh

Step-by-step explanation:

m

What is 200×300?

A. 60,000

B. 5,000

C. 50,000

D. 6,000​

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Answer:

A. 60,000

Step-by-step explanation:

The answer is A because 2 × 3 is 6 then you add the 4 0's. So it would be 60,000

Help me find out it.​

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Answer: The answer is 36

Answer: The answer is 36

PLEASE HELP ME WILL MARK BRAINLIEST!!

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Answer:

A line segment

Step-by-step explanation:

(3 x 10-7) x (8 x 10 )

Answers

Answer:

1840

Step-by-step explanation:

Answer:

2160

to solve this

(3*10-7) * (8*10)

(30 - 7) * (80)

27 * 80

= 2160

Please help find the volume in inches

Answers

Answer:

504 inches^3

Step-by-step explanation:

you multiple the height x length x width

May i get some help with a step by step concept of the first question please

Answers

9514 1404 393

Answer:

  J  3/4 cup

Step-by-step explanation:

Step 1: read and understand the question.

  The question is giving you amounts of flour and 2 types of sugar.

  The question is asking for a difference between two quantities:

the amount of flour (2 1/4 cups)the combined amount of sugar (3/4 cup white, 3/4 cup brown)

Step 2: determine the relations you need to use to solve the problem

   You need the combined amount of sugar, which you find by adding the quantities of each of the kinds.

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 You need the difference of that quantity from the quantity of flour, which you find by performing subtraction:

  flour - sugar = (2 1/4) - (6/4) . . . . cups

Step 3: Use your knowledge of arithmetic.

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Step 4: Answer the question that was asked.

  The difference between the flour and sugar amounts is 3/4 cup.

Here is the list of ingredients for making 30 biscuits.
Lucas has the following ingredients.
900 g butter
1000 g caster sugar
1000 g plain flour
225 g chocolate chips
What is the greatest number of biscuits Lucas can make?
You must show your working.
Ingredients for 30 biscuits
225 g butter
110g caster sugar
275 g plain flour
75 g chocolate chips

Answers

Answer:

90 biscuits

Step-by-step explanation:

900÷225=4

1000÷110=9

1000÷275=3

225÷75=3

Which of the following is represented by the expression below?

5x+2

aTwo more than five times a number
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cFive more than twice a number
dTwo more than 15 of a number
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Answers

Answer:

2 more than 5 times a number

Step-by-step explanation:

Problem #2: Ethan bought plates and cups for his upcoming birthday party. He
bought twice as many plates as cup. Altogether, he bought 102 items. How many
of each item did he buy?

Answers

Create an equation.

2c + c = 102

3c = 102

c = 34

Ethan buys 34 cups and 68 plates.

If cost of 15 eggs is ? 75, then find out the cost of 4 dozens eggs.

Answers

Answer:

Each egg is $5 so 4 dozen(48) is $240

Step-by-step explanation:

the way to do this is 75/15= 5

and then you multiply 12 x 4 to get 48 eggs

and then multiply 48 x 5 to get $240

15:75

divide each by 5

3:15

(4 dozen is 48 -> 48/3 = 16)

multiply each by 16

48: 240

240

Solve the system by graphing.

y = −x + 2
y = −4x − 1

The solution of the system is

Answers

Answer:

(-1,3)

Step-by-step explanation:

Answer the question below

Answers

Answer:

Well I know the formula but im not sure which option it matches to.

Step-by-step explanation:

3 x 3.5 times 1/2

+

11.4 x 10.5 times 1/2

4x+a=4x+3. How do you get to 6? Please explain and write down like you would write on paper. ​

Answers

Answer:

a=3 x= all reals

Step-by-step explanation:

I actually did not get 6 for an answer

4x+a=4x+3

cancel equal terms on both sides of the equation

a=3  

which means the x would be all reals cause it is true.

Use the diagram to solve for x.

Answers

Answer:

8

Step-by-step explanation:

You know that the horizontal lines are parallel to each other.

The 8 and x is both on that diagonal right there. Since the horizontal lines are parallel, that means the angle of 8 should have the same angle as x.

*I forgot what this thing was called but please trust me i learned this before*

1.The gradient of a straight line is the measure of the ratio of the
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change.

Answers

Answer:

The gradient of a straight line is the measure of the ratio of the vertical change to horizontal change

Step-by-step explanation:

Required

Fill in the gap

Gradient is calculated as:

[tex]m = \frac{y_2 - y_1}{x_2 - x_1}[/tex]

or

[tex]m = \frac{\triangle y}{\triangle x}[/tex]

Where [tex]\triangle[/tex] means change; y and x are vertical and horizontal change respectively


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Answers

Answer:32

Step-by-step explanation:

Answer:

190°

Step-by-step explanation:

Inscribed angle is half the measure of the intercepted arc:

m∠EFG = 1/2mEG1/2mEG = 95°mEG = 2*95° = 190°

What number is 16% of 46? Which equation and solution represents each situation?

Answers

Answer:

the answer to this question is 7.36....its equation is 16/100*46

Answer:

7. 36 is the answer.

Step-by-step explanation:

but, what equation, and what situations?

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Answers

Answer:

I think it is 6x+3=y (y=6x+3)

A. 20 mph
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Answers

girl it’s D, i’m kidding i don’t know but what grade are you in this looks easy

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Answers

Answer:

I am not really sure but try this -13/9 or -13 divided by 9

Step-by-step explanation:

Answer:

-13

Step-by-step explanation:

So, we're gonna use PEMDAS here. First, we have to subtract what's in the parentheses.

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The answer is -13

-3x + y = 1 4x + y = 8

Answers

-3x+y=1

/-3      /-3

x+y=-1/3

4x+y=8

/4      /4

x+y=8

---

hope it helps

Answer:

x=-1y-9

Step-by-step explanation:

find the solution of given expression

[tex] \sqrt{36 \times 36 \times 4} [/tex]

Answers

Answer:

√(36×36×4)=√(36²×2²)=±(36×2)=±72

[tex]\sqrt{36 \times 36 \times 4} = 72[/tex]

Show whether or not the points with coordinates (1,3) (4,2) (-2,6) are vertices of a right triangle

Answers

Answer:

No

Step-by-step explanation:

See attached

what is the area of a trapezoid that has a height of 12 and it’s parallel sides measure 15 and 20? Show the steps in your work.

Answers

Answer:

Area of trapezoid  = 210 unit²

Step-by-step explanation:

Given:

Height = 12 unit

Parallel side a = 15

Parallel side b = 20

Find:

Area of trapezoid

Computation:

Area of trapezoid  = [(a+b)/2]h

Area of trapezoid  = [(15+20)/2]12

Area of trapezoid  = 210 unit²

Ryan and Taylor are both saving money to buy new video game
equipment. Ryan's savings plan can be modeled by the function
s= 15m + 50 where m represents the number of months since Ryan
started his plan, and s represents the amount of money saved in
dollars. The table shown represents Taylor's savings plan.


Taylor's Savings Plan

Number of
Month Amount Saved ($)
0 25
1 45
2 65
3 85

Select the options that correctly complete the sentences.

greather or less than -----answer

Ryan's rate of change is ________ Taylor's rate of change .

Ryan'sstaring balanced is_______ Taylor's starting balanced.​

Answers

We want to compare the rates of change and starting balances of Ryan and Taylor, the correct answers are:

"Ryan's rate of change is _less than_ Taylor's rate of change.""Ryan's starting balance is greater than Taylor's starting balance.​"

So we know that Ryan's savings plan can be modeled by:

S(m) = 15*m + 50.

This means that he starts with 50, and saves 15 per month, then:

Ryan's rate of change = 15 per monthRyan's initial balance = 50

For Taylor we have a table:

month    amount saved:

0                 25

1                  45

2                 65

3                 85

So, in month 0 he has 25, thus, his initial balance is 25.

And each month the amount saved increases by 20, then the equation is:

T(m) = 20*m + 25

Then we have:

Taylor's rate of change = 20 per month.Taylor's initial balance = 25

Now we can see that:

"Ryan's rate of change is _less than_ Taylor's rate of change."

"Ryan's starting balance is greater than Taylor's starting balanced.​"

If you want to learn more about rates of change, you can read:

https://brainly.com/question/18904995

Mrs. Crosland asked students to factor the expression 28x - 8. The students offered the answers shown

Carlos: 2(14x - 4)
Danny: 7(4x - 1)
Irene: 4(7x - 2)

Which student(s) offered answer(s) equivalent to the original expression?

Answers

Answer: Irene
Explanation

Equivalent expression for the given expression is

4(7x-2)

Irene offered answer equivalent to the original expression

Given :

Mrs. Crosland asked students to factor the expression 28x - 8

The student are given some expression . To find correct expression , we need to factor the given expression

[tex]28x-8[/tex]

Both 28 and 8 are divisible by 4

Lets factor out 4 from the given expression.

When we factor out 4, then we divide each term by 4

[tex]28x-8\\4(\frac{28}{4} -\frac{8}{4} )\\4(7x-2)[/tex]

The students offered the answers shown

Carlos: 2(14x - 4)

Danny: 7(4x - 1)

Irene: 4(7x - 2)

so , from the answer we can say that Irene offered answer equivalent to the original expression

Learn more :  brainly.com/question/22345708

Which equation can be used to answer the question below?
Christopher made 12 of the 40 recipes he downloaded from the Internet. What percent of the recipes did he make?
A X=12(40)
B 12x=40
C 12=x/40
D 12=40x

Answers

Christopher made 30% of the recipe downloaded

He made 12 of the 40 recipes he downloaded from the internet.

He downloaded a total of 40 recipes.

Percentage

Percentage is is a number or ratio that can be expressed as a fraction of 100. Therefore,

The percentage of the recipe he made can be calculated as follows;

percentage of recipe made = 12 / 40 × 100

percentage  = 1200 / 40 = 30%

Therefore, he made 30% of the recipe downloaded

learn more on equation here: https://brainly.com/question/4345896

Ivan has $50,000 in a savings account that earns 4% interest per year. The interest is not compounded. To the nearest dollar, how much interest will he earn in 5 years?

Answers

Answer:

$2,000

Step-by-step explanation:

4% of $50,000 is $2,000 so 2,000 X 5 =10,000

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