The half-life of Iodine-131 is approximately 8 days. Find the amount of Iodine-131 left from a 42 gram sample after 16 days.


1) 0.0006 grams

2) 21 grams

3) 10.5 grams

4) 34 grams

Answers

Answer 1

Answer:

Step-by-step explanation:

The formula for this is

[tex]N=N_0(.5)^{\frac{t}{H}[/tex] where

N is the amount of the element left after a certain amount of time (for us it is measured in days),

N₀ is the initial amount of the element in grams,

t is the number of days gone by, and

H is the half life of the element. Filling in:

[tex]N=42(.5)^{\frac{16}{8}[/tex] which simplifies a bit to

[tex]N=42(.5)^2[/tex] and a bit more to

N = 42(.25) which gives us a remaining amount of

N = 10.5


Related Questions

Insurance companies are interested in knowing the population percent of drivers who always buckle up before riding in a car. They randomly survey 387 drivers and find that 298 claim to always buckle up. Construct a 84% confidence interval for the population proportion that claim to always buckle up.

Answers

Answer:

The 84% confidence interval for the population proportion that claim to always buckle up is (0.74, 0.80).

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

They randomly survey 387 drivers and find that 298 claim to always buckle up.

This means that [tex]n = 387, \pi = \frac{298}{387} = 0.77[/tex]

84% confidence level

So [tex]\alpha = 0.16[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.16}{2} = 0.92[/tex], so [tex]Z = 1.405[/tex].

The lower limit of this interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.77 - 1.405\sqrt{\frac{0.77*0.23}{387}} = 0.74[/tex]

The upper limit of this interval is:

[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.77 + 1.405\sqrt{\frac{0.77*0.23}{387}} = 0.8[/tex]

The 84% confidence interval for the population proportion that claim to always buckle up is (0.74, 0.80).

Combine any like terms in the expression. If there are no like terms, rewrite the expression.
5t+t–2t

Answers

Answer:

4t

Step-by-step explanation:

Note that teach term has the variable t in it. Also, note that if t is by itself, it actually means 1t. Combine the given constants:

5t + 1t - 2t

= (5t + 1t) - 2t

= (6t) - 2t

= 4t

4t is your answer.

~

A die is rolled 2 times. What is the probability of getting a 2 on the first roll and a 5 on the second roll?

Answers

Answer:

1/36

Step-by-step explanation:

the chance of rolling a 2 on a 6-sided die is 1/6 and rolling a 5 on a 6-sided is also 1/6.

So, 1/6 * 1/6 = 1/36

Hope this is helpful

Answer:

Step-by-step explanation:

six sided die gives you 6 possibilities

probability of rolling a 2 is 1/6

probability of rolling a 5 on the second roll is 1/6

What is the radius of a sphere with a volume of 62770 m, to the nearest tenth of a
meter?

Answers

Answer:

24.65

Step-by-step explanation:

Oscar bought 12 lunches for 30$ what was the unit cost

Answers

Each lunch cost him $2.50

$30 / 12 = 2.5
the unit cost is $2.50

Order from least to greatest

1/8, 11/12, 9/8​

Answers

Answer:

Step-by-step explanation:

First make the denominators the same.

Take the LCM of (8, 12 , 8) = 24

So,

      [tex]\frac{1}{8}, \frac{11}{12}, \frac{9}{8} \ becomes \ \frac{3}{24}, \frac{22}{24}, \frac{27}{24}[/tex]

[tex]Order \ from \ least \ to \ greatest \ \\\\\frac{3}{24} < \frac{22}{24} < \frac{27}{24}[/tex]

That is,

           [tex]\frac{1}{8}, \frac{11}{12}, \frac{9}{8}[/tex]

The owners of an amusement park selected a random sample of 200 days and recorded the number of park patrons with annual passes who visited the park on each selected day. They computed a 90% confidence interval for the number of patrons with annual passes who visit the park daily. How would you interpret the 90% confidence interval of (35, 51)? a. There is a 90% chance that the population mean number of patrons with annual passes who are in the park on any given day is between 35 and 51. b. The method used to calculate the confidence interval has a 90% chance of producing an interval that captures the population mean number of annual pass holders in the park on any given day. c. Ten percent of the population of annual pass holders visit the park on any given day. d. There is a 90% chance that the sample percentage of park patrons with annual passes is contained in the interval 35 to 51.

Answers

Answer:

b. The method used to calculate the confidence interval has a 90% chance of producing an interval that captures the population mean number of annual pass holders in the park on any given day.

Step-by-step explanation:

The confidence interval calculated from the sample at a particular confidence level, gives a certain percentage of confidence based on the confidence level that the true mean of the population exists within the confidence interval Calculated.

For the scenario above, we can say that there is a 90% chance that the population mean number of annual pass holders in the park on a given day is within the interval (35, 51)

Can somebody help me with this

Answers

Answer:

0.04997916927

Step-by-step explanation:

Answer:

30 degrees

Step-by-step explanation:

arcsin(0.5) deg

= 30

You start at (2, -1). You move down 3 units and left 3 units. Where do you end?

Answers

Answer:

(-1,-4)

Step-by-step explanation:

(2, -1)

Moving down 3 means subtract 3 from the y value

Left 3 means subtract 3 from the x value

(2-3, -1-3)

(-1,-4)

(-1,-4) is the answer

Can someone please help?

Answers

it is 7/8 the last one
7/8 because 3+4=7 and since the denominator is the same we dont have to change it

What is the M.A.D. of this data set? 3,6,6,7,8,11,15,16

Answers

the answer is 8 because it was in the middle

it's 8

Question 20
Josh says that has the same quotient as Is this true or false?
O True
O False

Answers

Josh says that has I don’t understand..

A pyramid and a cone are both 10 centimeters tall and have the same
volume. What statement must be true about the two solids?

A. The vertical cross-sections of the pyramid and cone at the same
width must have the same area.
B. The cross-sections of the pyramid and cone are the same shape.
C. The area of the cross-sections of the pyramid and cone are
multiples of each other.
D. The horizontal cross-sections of the pyramid and cone at the
same height must have the same area.

Answers

Answer:

D the horizontal cross-section of the pyramid and cone at the same height must have the same area

divide k800. in the ratio of 5:3​

Answers

Answer:

k500: k300

Step-by-step explanation:

5 parts :3 parts

there are 5+3=8 parts in total

800 divide by 8 parts = 100 in each part

k800 is 5:3  is k500: k300

6x-5

Step-by-step explanation:

4/5÷4/10

12×2 -64×-11,×+1

×3-×2+7×

___________

6x-5 answer

PLS HELP ASAP! WILL GIVE U BRAINLIEST
Valid or Invalid: If a number is even, then it is a multiple of 4.
A. Invalid

B. Valid

Answers

Answer:

valid

Step-by-step explanation:

it's valid because for example here are some even numbers, 0, 2, 4, 6, 8, they're are all multiples of four.

hope that helped :)

mark me brainliest pls

How does the distance traveled and time elapsed compare for Carrie and Kevin as they traveled from mile marker 225 to mile marker 230?

Answers

Answer:

This implies that they traveled the same distance and they spend the same amount of time from 225 to 230 mile marker

Step-by-step explanation:

Given

See attachment for graph

Required

Compare the distance and time travel

From the attached graph, we have the origin to be (0,0).

This represents the mile marker 225

Mile marker 230 is represented by point 5 on the y-axis.

Kevin's line at point 5 is represented as: (16,5)

Carrie's curve at point 5 is represented as: (16,5)

Both points are equal; i.e.

[tex](16,5) =(16,5)[/tex]

This implies that they traveled the same distance and they spend the same amount of time from 225 to 230 mile marker

Determine how many people will fit in a building with a width of 105 feet and a length of 250 feet, if we use a standard of 16 people per 25 square feet.

Answers

Answer:

16,800 people

Step-by-step explanation:

105 * 250 = 26,250

p = 26250ft² * (16 people / 25ft²)

p = 16,800 people

Answer:

16800

Step-by-step explanation:

105 x 250 = 26250 and then divide it by 25 which is 1050 then multiply by 16 which is 16800

Hope this helps!

WORTH 20 POINTS


Use the volume formula to find the volume of the prism.






A. 9 cubic units O

B. 18 cubic units

C. 4 cubic units O

D. 7 cubic units

Answers

9514 1404 393

Answer:

  A.  9 cubic units

Step-by-step explanation:

We interpret the smudges in your attachment to be dimensions of 1 1/2, 4, and 1 1/2. The volume is the product of these.

  V = LWH

  V = (4)(1.5)(1.5) = 9 . . . . cubic units

The volume of the prism is 9 cubic units.

Interpret the results of the chi-square test.A die is rolled 180 times and the following data are obtained.Number Frequency 1 31 2 34 3 26 4 16 5 32 6 41A chi-square test was conducted to determine, at the 5% significance level, whether or not the die is loaded (i.e., that the six numbers are not equally likely).Carry out the hypothesis test.

Answers

Answer:

Step-by-step explanation:

From the given information:

Null and alternative hypothesis is:

[tex]\mathbf{H_o: \text{The die is not loaded i.e. six numbbers are equally alike}}[/tex]

[tex]\mathbf{H_a: \text{The die is loaded i.e. six numbbers are not equally alike}}[/tex]

Numbers   Observed         Expected            (O - E)    (O-E)^2     (O-E)^2/E

                 Frequency (O)   Frequency (E)  

1                  31                             30                   1             1               0.03

2                 34                            30                   4             16            0.53

3                 26                            30                  -4            16             0.53

4                 16                             30                  -14           196           6.53

5                 32                            30                    2            4               0.13

6                 41                             30                    11            121            4.03

Total          180                                                 [tex]X^2= \sum (\dfrac{O-E}{E})^2=11.78[/tex]

degree of freedom = n - 1

= 6 - 1

= 5

Critical value at [tex]X^2_{0.05/2,5} =11.07[/tex]

Since the calculated [tex]X^2 \ is \ > X^2_{0.025/5}[/tex] , then we reject [tex]H_o[/tex]

Conclusion: Accept the alternative hypothesis.

The information provided gives sufficient evidence for us to conclude that the given die is loaded.

Joey, Mikey, and Anna each bought an equal number of comic books. If Anna
went home with six comic books, how many did the group buy?
Answer: 6, 2, 12, 18 I NEED HELP PLEASE

Answers

Answer:

the group bought 18 comic books.

Step-by-step explanation:

It says that Anna went home with 6 comic books and there are 3 people (Joey, Mikey, and Anna). So if Anna bought 6 comic books, Joey also bought 6 books and Mikey also bought 6 books. 6 + 6 + 6 = 18

Hope this is helpful

Can someone explain to me the Laws of Sine and Cosine. Will mark brainliest.

Answers

Answer:

here you are

i hope it helps! :)

Step-by-step explanation:

The Law of Sines establishes a relationship between the angles and the side lengths of ΔABC: a/sin(A) = b/sin(B) = c/sin(C). Sine is always positive in this range; cosine is positive up to 90° where it becomes 0 and is negative afterwards

Find the slope on the line?

Answers

Answer:

slope=0

Step-by-step explanation:

Hi there!

We're given a graph with a line and two marked points on the graph: (-1,3) and (3,3)

the formula given for slope calculated from two points is (y2-y1)/(x2-x1), where (x1,y1) and (x2,y2) are points

we have our two points: (-1,3) and (3,3) and we can label them:

x1=-1

y1=3

x2=3

y2=3

now substitute into the formula

note: Remember the formula shows SUBTRACTION, even though we have NEGATIVE numbers. When we simplify, we'll add the numbers.

slope=(3-3)/(3--1)

simplify

slope=0/4

divide

slope=0

Hope this helps!

Convert the equation into standard form 25x^2 -9y^2+200x +18y +166=0

Answers

Answer:

Step-by-step explanation:

You'd have to be really familiar with conic sections to know what to do with this. Good thing I am! ; )

Begin by grouping the x terms together and the y terms together, and getting the constant on the other side of the equals sign:

[tex]25x^2+200x-9y^2+18y=-166[/tex]

Now we need to complete the square on the x terms and the y terms. Do this by first factoring out the leading coefficient from each, the 25 from the x's and the 9 from the y's:

[tex]25(x^2+8x)-9(y^2+2y)=-166[/tex]

Now take half the linear term in each set of parenthesis, square it, and add it in to both sides, remembering the multiplier outside (the 25 and the 9). Our x linear term is 8. Half of 8 is 4, and 4 squared is 16, so we add a 16 into the parenthesis with the x's; our y linear term is 2. Half of 2 is 1 and 1 squared is 1, so we add a 1 into the parenthesis with the y's:

[tex]25(x^2+8x+16)-9(y^2+2y+1)=-166+400-9[/tex]

Note the 400 and -9 on the right side now. 25 times 16 is 400; we didn't just add in a 16, we have to multiply the scalar number into it before we know what we REALLY added in. And the -9 comes from multiplying the -9 times 1.

The reason we do this is to get the perfect square binomials on the left that we created while completing the square:

[tex]25(x+4)^2-9(y+1)^2=225[/tex]

Now, finally we will divide both sides by 225 to get this conic into standard form:

[tex]\frac{(x+4)^2}{9} -\frac{(y+1)^2}{25} =1[/tex]

This is a hyperbola with a horizontal transverse axis and a center of (-4, -1). The reason we know it's not an ellipse is because an ellipse will always have a + sign separating the x-squared from the y-squared whereas a hyperbola always has a - sign separating them. And we also know it's not a circle because the values of the leading coefficients weren't the same.

Lin and Claire each threw a rock into a stream. The black graph represents the height of a stone t seconds after it was tossed up by Lin and the purple graph represents the height of a stone t seconds after it was tossed up by Claire.
1) Whose stone hit the water second, and at what time?

2) How long did it take for Claire's rock to reach its maximum? What is the maximum height?

3) Who had the higher initial height? What was it?

Answers

Answer:

1) claire's stone at 1.25 seconds

2) 0.5 seconds and its max height was 9

3) lin at 8ft

Step-by-step explanation:

the intercepts tell you the first and third question and then the max height is the highest point on the graph

not sure what measurements you were supposed to use so I used seconds and feet and if that's not it then it's the same numbers just different words

what is 12.92÷10 to the power of five
than you

Answers

Answer:

0.0001292

Step-by-step explanation:

a raised to the power -m is 1/a raised to power m

(t+5)(t+2),make t the subject of the formula​

Answers

Answer:

t= 2p+5/p-1

Step-by-step explanation:

The question is not well writen

Assume p = t+5/t-2

We are to make t the subject of the formula

Cross multiply

p(t-2) = t+5

pt - 2p = t+5

pt - t = 2p+5

t(p-1) = 2p+5

t= 2p+5/p-1

Hence the value of t is 2p+5/p-1

Can someone please help me on this work I really need help I will but you brainly

Answers

Answer:

-3 1/4 is the answer for this question

is (0,0) a solution to this system

Answers

is (0,0) a solution to what system?

10 points will give brainliest

Answers

Answer:

A. 9/2 × 3/8

Step-by-step explanation:

______________

A - 9/2 x 3/8
hope this helps

rearrage and solve 4t-s-2t+25​

Answers

Answer:

See the image below for the answer:)

Step-by-step explanation:

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