The half-life of radium is 1690 years. If 80 grams are present now, how much will be present in 870 years?
grams

Answers

Answer 1

Answer:

A(t) = amount remaining in t years

= A0ekt, where A0 is the initial amount and k is a constant to be determined.

Since A(1690) = (1/2)A0 and A0 = 80,

we have 40 = 80e1690k

1/2 = e1690k

ln(1/2) = 1690k

k = -0.0004

So, A(t) = 80e-0.0004t

Therefore, A(430) = 80e-0.0004(430)

= 80e-0.172

≈ 67.4 g

Step-by-step explanation:

hope it helpful for you ❤️


Related Questions

An experiment is conducted examining the effects of a new type of toothpaste on reducing cavities. Individuals in the treatment condition are given the new toothpaste; individuals in the control condition are given the standard toothpaste, but are told that they're receiving the new toothpaste. At the end of the experiment, the control group participants demonstrate a slightly higher decline in cavities. This is an example of a(n):____.
a. Wording bias.
b. Voluntary response bias.
c. Over-sampling effect.
d. Placebo effect.
d. Hawthorne effect.

Answers

The experimental effect highlighted by the scenario described would most likely be an example of placebo effect.

An observed change in the control group which are being given the placebo would have been triggered due to psychological expectation based on the information given. Hence, this is called the placebo effect.

The standard toothpaste was not suppose to cause decline in cavities, however, since the group have been told that they we given the new toothpaste which is said to reduce cavities, this could trigger a psychological change hence causing them to have higher cavity decline.

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if there are 60 houses and every house have one kid and there's 30 parts how much kids will have to go to each Park

Answers

Answer:

2 parks

Step-by-step explanation:

Answer:

20

Step-by-step explanation:

There would be 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

Parents of children with developmental disorders can apply for federal funding for psychosocial rehabilitation. A government sociologist wants to know what percentage of applicants for this funding are in poverty. She obtains access to all their applications, groups the applications by state, and takes a simple random sample from each state's applications. Identify the population of interest to the sociologist.

a. Applicants for the federal funding who were in poverty
b. Applicants for the federal funding
c. Applicants who received the federal funding
d. Applicants whose applications were examined

Answers

Answer:

Applicants for the federal funding

Step-by-step explanation:

A parking lot has 117 spaces total. If 36 of the spaces have cars in them, what is the ratio of empty spaces to filled spaces?

Answers

Answer:

81:36

Step-by-step explanation:

117-36

= 81

Boom answer that's it

The ratio of empty spaces to filled spaces is 9 : 4.

What is proportion ?

A proportion is an equation based on the equality of two ratios.

Here it is given that :

A parking lot has total = 117 spaces

Spaces filled with cars = 36

spaces left = total spaces - space filled with cars

spaces left = 117 - 36

spaces left = 81

Now, the ratio of empty spaces to filled spaces will be :

81 : 36

cancelling common factor that is 9 :

9 : 4

Therefore, the ratio of empty spaces to filled spaces is 9 : 4.

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PLEASE ANSWER FAST BUT CORRECTLY

Answers

Shordy that’s too much work smfh

Answer:

A-quadratic

B [tex]- \infty\leq x\leq \infty[/tex]

C [tex]-1\leq x\leq \infty[/tex]

D -3.7071 and -2.2929

E 17

F (-3, -1)

G(17,0) (-2.2929  -3.7071)

h(17,0)  -3.7071,0)

j even

At a birthday party, 20% of the guests wear glasses.

If there are 30 guests, how many wear glasses?

Answers

Answer: 6
20x30=600
600/100=6
6 guests were wearing glasses

Answer:

if 100% =30 guests what about 20%=6%

Help I offer all of my points

Answers

Answer:

100 bags

Step-by-step explanation:

You're going to want to multiply each amount of pounds the bags are by two. So 30 × 2 is 60. 15 × 2 = 30. 5 × 2 = 10.

60 + 30 = 90

90 + 10 = 100                            (BRAINLIEST PLEASE OvO)

(x + 1)(x - 1)
I dont understand this could any1 help me

Answers

Answer:

x^2-1

Step-by-step explanation:

you must use the distributive property

first you do x•x=x^2,

then you do x•1 and x•-1 to get x and -x and those cancel out,

the you do 1•-1=-1, then you put it together to get x^2-1

Step-by-step explanation:

It's a factored form of the quadratic equation

[tex] {x}^{2} - 1[/tex]

in the form of [tex] {ax}^{2} + bx + c[/tex]

in which a = 1, b = 0, c = 1.

number 4. and 5.
What is the unit rate for each size?
Which size is a better buy? why?

Answers

Answer:

Step-by-step explanation:

4)

Regular  $4 / 8 cups = $0.50 / cup

Large    $6 / 15 cups = $0.40 / cup

5)

most people would consider the Large to be the better buy because the price per cup is lower.

please answer fully///////////////

Answers

I think it’s 14

I hope you have a wonderful day!

Answer:

14

Step-by-step explanation:

(4+(16-1)/5)*2

(4+15/5)*2

(4+3)*2

7*2

14

Which of the following statements is incorrect?
a. (-3x)3 = -27x3
b. xo xx-4 = x2
c. x + x-3 = x4
d. 3-2 = -9

Answers

Answer:

The last one is incorrect

What is the equation of this line?

Answers

Answer:

y = 1/2x - 3

Step-by-step explanation:

Evaluate the expression( 3x2)2

Answers

Answer:

12

Step-by-step explanation:

Its 12 because you would do what’s in the parentheses first, which is 3x2 which is 6, then multiply it by 2. 6x2=12.

Determine the value of x. Round to the tenths place. 30/4 65/x​

Answers

wow that's really hard... :) greetings from South Korea My name is Naoyoung nei The abbreviation of Nanda is Naoyoung nei And the name DA is the name of my father and mother

Lin father is paying for a 20 meal he has a 15 off coupon for the meal what is the total after the discount

Answers

Answer:

3

Step-by-step explanation:

20÷100=0.2

0.2×15=3

:)

Answer:

Lin's father would pay $17 for his meal.

Step-by-step explanation:

15*20 = 300

300/100 = 3

20 - 3 = 17

135 rational or irrational ​

Answers

Answer:

Rational

Step-by-step explanation:

I hope this helps!

It is an Irrational number

Trish has 7 cans of dog food for 3 days. She will feed each dog 2 1/3 cans of food each days. If she wants to feed them 3 cans each day how many more cans of food will she need

Answers

Answer:

2 more cans

Step-by-step explanation:

2 1/3 x 3 = 7 cans (this the amount of cans of dog food she has)

3 x 3 = 9

the 3 represents how she wants to feed 3 cans of dog food each day for 3 days; the other 3 represents 3 days

9 - 7 = 2

A contractor uses a scale drawing of an office floor to determine the amount of carpet he needs to buy 1/4 inch = 4.5 feet the width in the scale drawing of the office floor is 6.4 inches what is the actual width of the office floor

Answers

A scale drawing is a method of drawing that requires either increasing or decreasing the dimensions of a given object. So then, the actual width of the office floor is: 115.2 feet.

A representative factor is a factor the can be used to either increase or decrease the dimensions of an object. It is sometimes referred to as a scale factor.

In the given question, the scale factor is given as:

[tex]\frac{ 1 }{4}[/tex] inch = 4.5 feet

Given that the width in the scale drawing of the office floor is 6.4 inches, let the actual width be represented by x.

So then;

[tex]\frac{ 1 }{4}[/tex] inch = 4.5 feet

6.4 inches = x

x = [tex]\frac{6.4 *4.5}{\frac{1}{4} }[/tex]

  = [tex]\frac{28.8}{0.25}[/tex]

x = 115.2

Therefore, the actual width of the office floor is 115.2 feet.

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Answer:

115.2                                                                /\

Step-by-step explanation:                         /     \

What the person above me said.             /         \

16.
Identify the axis of symmetry of the parabola.

A. x = -2

B. x = 1

C. x = -3

D. x = -1

Answers

Answer:

i don't know

Step-by-step explanation:

In February Lana got a puppy that weighed 13 kilograms. By October the puppy weighed 16.9 kilogram. What was the puppy’s weight increase?.

Answers

16.9 minus 13 equals to 3.9 increase

Answer:

3.9

Step-by-step explanation:

16.9 take away 13 and you get 3.9 kilograms

no link no bot right answer

Answers

the answer is 4 inches

HELP CODE HS 3.2.8 repeating message

Answers

The program is an illustration of loops.

Loops are used to perform iterative and repetitive operations.

The program where comments are used to explain each line is as follows:

public class MyProgram extends ConsoleProgram {

   public void run()     {

//This prompts the user for the number of times to repeat the message

       echo("Anybody home?", readInt("Times to repeat: "));

   }

    private void echo(String lineOne, String lineTwo, int numTimes)     {

//The following iteration is repeated numTimes times

       for (int i = 0; i < numTimes; i++){

//This prints lineOne

       System.out.println(lineOne);

//This prints lineTwo

       System.out.println(lineTwo);

       }

   }

}

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Given that angle a = 54° and angle b = 48°, work out 3.
a
b
х
The diagram is not drawn accurately.
х

Answers

9514 1404 393

Answer:

  x = 78°

Step-by-step explanation:

The sum of the interior angles of a triangle is 180°.

  x + a + b = 180°

  x = 180° -a -b . . . . . . . . add -a-b to both sides

  x = 180° -54° -48°

  x = 78°

If right you get brainiest!
A little mermaid can swim 12 miles downstream in the same amount
of time she can swim 8 miles upstream. What is the little mermaid's
speed in still water if the speed of the current is 4 mph?

Answers

Answer:

20 mph

Step-by-step explanation:

time = distance / speed

speed up stream = s - 4

speed down stream = s + 4

time up = time down

8 / (s - 4) = 12 / (s + 4)

cross multiply

8s + 32 = 12s - 48

subtract 8v from both sides

32 = 4s - 48

add 48 to both sides

80 = 4s

Divide both sides by 4

20 = s

20mph

If 2 pizzas cost $16, how much do 4 pizzas cost?

Answers

Answer:

$32

Step-by-step explanation:

$16/2 pizzas = $8 per pizza

($8)(4)=$32

Answer:

$32

Step-by-step explanation:

16/2 is 8. So each pizza costs exactly 8 dollars. You have to do 4x8 which is 32

HELP FAST PLS I’ll mark u brainliest

Answers

Answer:

about 20 cents

Step-by-step explanation:

#Shop A

Pack of 10pens=£2.30

Pack of 70pens:-

[tex]\\ \sf\longmapsto 7(2.30)=16.10[/tex]

#2

Pack of 5=1.60£

Pack of 70

[tex]\\ \sf\longmapsto 14(1.60)=20.80[/tex]

But you get half price

20.80/2=10.40

Difference:-

[tex]\\ \sf\longmapsto 16.10-10.40=5.70\£[/tex]

Express 405 1/3 in simplest radical form.

Answers

Answer:

3 cube root of 15

Step-by-step explanation:

theres your simple radical form

8(152/3) is 405 1/3 in simplest radical form.

What is simplification?

Simplifying procedures is one way to achieve uniformity in job efforts, expenses, and time. It reduces diversity and variation that is pointless, harmful, or unneeded. Parenthesis, exponents, multiplication, division, addition, and subtraction are all referred to as PEMDAS. The order of the letters in PEMDAS informs you what to calculate first, second, third, and so on, until the computation is finished, given two or more operations in a single statement.

405 1/3 is equivalent to (405*3 + 1)/3 = 1216/3.

To express 1216/3 in simplest radical form, we can first simplify it by dividing both the numerator and denominator by their greatest common factor, which is 8.

1216/3 = (8*152)/3 = 8(152/3)

Now, we can see that 152/3 cannot be simplified any further, so the simplest radical form of 405 1/3 is: 8(152/3)

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A ticket for a show costs ​$114.50. A parking pass costs ​$13.00. Let x represent the number of tickets and y represent the cost. How much does it cost for 2 tickets and a parking​ pass?

Answers

Answer:

X multiplied by Y is $229 plus a parking pass being $242

Step-by-step explanation:

X = 2 (2tickets)

Y = $114.50 (cost of one)

multiplying the tickets by the cost of one will give you $229 and the cost for the parking pass being $13.00 well 29 + 13 = 42 adding 42 to the 200 we left gives you $242 for 2 tickets and a parking pass

a pacific seahorse eats about 56 shrimp per week how much does it eat per day

Answers

56 divided by 7
Equals 8

8 is the answer

At gym A is 76.50 for 8.5 hours. At gym B cost is 10.50 for 3/4 hours which plan of offers the best deal

Answers

The better deal is gym a.

Tell me if you want step by step explanation!

Hope this helped. :)
Gym A is the correct answer.
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