The half-life of a radioactive substance is the time it takes for a quantity of the substance to decay to half of the initial amount. The half-life of the radioactive gas radon is approximately 2.8 days. The initial amount of radon used in an experiment is 74 grams. If N represents the number of grams of radon remaining t days after the start of the experiment,
a. Write an equation that gives Nin terms of t.
b. how much gas radon approximately remains after 2.8 days?
c. approximately when will the amount of radon remaining be 10 grams?

Answers

Answer 1

Step-by-step walkthrough:

a.

Well a standard half-life equation looks like this.

[tex]N = N_0 * (\frac{1}{2})^{t/p[/tex]

[tex]N_0[/tex] is the starting amount of parent element.

[tex]N[/tex] is the end amount of parent element

[tex]t[/tex] is the time elapsed

[tex]p[/tex] is a half-life decay period

We know that the starting amount is 74g, and the period for a half-life is 2.8 days.

Therefore you can create a function based off of the original equation, just sub in the values you already know.

[tex]N(t) = 74g * (\frac{1}{2})^{t/2.8days[/tex]

b.

This is easy now that we have already made the function. Here we just reuse it, but plug in 2.8 days.

[tex]N(t) = 74g * (\frac{1}{2})^{t/2.8days} = N(2.8days) = 74g * (\frac{1}{2})^{2.8days/2.8days}\\= 74g * \frac{1}{2} = 37g[/tex]

c.

Now we just gotta do some algebra. Use the original function but this time, replace [tex]N(t)[/tex] with 10g and solve algebraically.

[tex]10g = 74g * (\frac{1}{2})^{t/2.8days}\\\\\frac{10g}{74g} = (\frac{1}{2})^{t/2.8days}[/tex]

Take the log of both sides.

[tex]log(\frac{5}{37}) = log((\frac{1}{2})^{t/2.8days})[/tex]

Use the exponent rule for log laws that, [tex]log(b^x) = x*log(b)[/tex]

[tex]log(\frac{5}{37}) = \frac{t}{2.8days} * log(\frac{1}{2})[/tex]

[tex]\frac{log(\frac{5}{37})}{log(\frac{1}{2})} = \frac{t}{2.8days}[/tex]

[tex]2.8 * \frac{log(\frac{5}{37})}{log(\frac{1}{2})} = t[/tex]

slap that in your calculator and you get

[tex]t = 8.1 days[/tex]


Related Questions

The owners of cami's carnival kept track of how many visitors they had each day last summer. this box plot shows the results. carnival visitors 50 70 90 110 130 150 what fraction of the days did the carnival have 70 or fewer visitors?

Answers

Answer: 1/3

Step-by-step explanation: 50, and 90, 2/6 reduces to 1/3.................2 pp ignore the 2 and p I'm in mobile

Vat=13% Discount=20% Sp with vat=20340 Mp=? Vat amount=?

Answers

Answer:

Vat amount = Rs 2340

Mp = Rs 22500

solve pls brainliest

Answers

Answer:

decreased by 7

Step-by-step explanation:

Based off of the table after each day, the money left on the card decreases by 7 after each day

eg. On Monday there is $40 on the card. On Tuesday there is $33 on the card. The money on the card decreases by 7 from Monday to Tuesday. It continues to decrease by this constant amount as the days pass.

Answer:

With each day additional day, the amount left on the card decreased by $7

Step-by-step explanation:

After each day you could see that the amount of money was lower and if you subtracted Monday by Tuesday, Tuesday by Wednesday, Wednesday by Thursday, and Thursday by Friday, you could see that it fell $7 each time.

reduce into lowest terms

[tex] \frac{4}{6} [/tex]
[tex] \frac{10}{12} [/tex]
[tex] \frac{18}{24} [/tex]

Answers

Answer:

4/6

We know that, 4 can be written as:

4 = 2 × 2 and 6 = 2 × 3.

In both 2 is common so cancel it out we get, 2/3

Similarly,

10/12

10 = 2 × 5 and 12 = 2 × 2 × 3

2 common and cancel we get, 5/6

18/24

18 = 2 × 3 × 3

24 = 2 × 2 × 2 × 3

6 (2 × 3) is common. So, cancel we get, 3/4

40 points answer ASAP
A manager is assessing the correlation between the number of employees in a plant and the number of products produced monthly. The table shows the data:


Number of employees
(x) 0 10 20 30 40 50 60 70 80
Number of products
(y) 120 200 280 360 440 520 600 680 760


Part A: Is there any correlation between the number of employees in the plant and the number of products produced monthly? Justify your answer. (4 points)

Part B: Write a function that best fits the data. (3 points)

Part C: What does the slope and y-intercept of the plot indicate? (3 points)

Answers

Answer: See below

Step-by-step explanation:

a) There is a correlation between the number of employees in the plant and the number of products produced yearly. Specifically, a positive correlation exists because, as we can see on the table, as the number of employees increases, the number of products also increases. And the rate of increase is constant.

b) Let the function be: y = mx + b

When x = 0; y = 120

So:

120 = 0 + c

c = 120

Now the slope:

[tex]\text { Slope }=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}=\frac{200-120}{10-0}=\frac{80}{10}=8[/tex]

Therefore, the equation that best fits the data is y = 8x + 120

c) The slope in the function represents the constant rate of change, meaning that as the number of employees increases by 1, the number of products produced monthly increases by 20. While the y-intercept of the plot, which is 120, indicates the constant number of products, that is to say, when there are no employees, there are still 120 products.

The are 3 blue marbles, 4 red marbles and 2 yellow marbles. Find the ratio of blue marbles to red and yellow marbles.

Question 2 options:

3:2


4:3


3:4


1:2

Answers

Answer:

3;4

Step-by-step explaining

do the first to ratios the 3rd doesnt matter

The ratio of blue marbles to red AND yellow marbles would be 1:2. You need to add the red and yellow marbles together which equals 6 marbles. Now that you have 3 blue and 6 red/yellow marbles, you can simplify the 3:6 ratio down to 1:2.


:

factorise: x^4– 5x^2 + 4​

Answers

Answer:

(x - 2)(x - 1)(x + 1)(x + 2)

Step-by-step explanation:

[tex] {x}^{4} - 5 {x}^{2} + 4 \\ \\ = {x}^{4} - 4 {x}^{2} - {x}^{2} + 4 \\ \\ = {x}^{2} ( {x}^{2} - 4) - 1( {x}^{2} - 4) \\ \\ = ( {x}^{2} - 4)( {x}^{2} - 1) \\ \\ = (x + 2)(x - 2)(x + 1)(x - 1) \\ \\ = (x - 2)(x - 1)(x + 1)(x + 2)[/tex]

Answer:

[tex](x+1)(x-1)(x+2)(x-2)[/tex]

Step-by-step explanation:

To factorise  [tex]x^4-5x^2+4[/tex] :

Let [tex]x^2=u[/tex]

[tex]\implies x^4-5x^2+4=u^2-5u+4[/tex]

Now factorise  [tex]u^2-5u+4[/tex]

[tex]\textsf{for} \ ax^2+bx+c \ \textsf{find} \ v, w \ \textsf{such that} \ v \cdot w=a \cdot c \ \textsf{and} \ v+w=b[/tex]

[tex]\textsf{and group into} \ (ax^2+vx)+(wx+c)[/tex]

[tex]\implies v=-1, w=-4[/tex]

[tex]\implies u^2-u-4u+4[/tex]

Break into groups

[tex]\implies (u^2-u)+(-4u+4)[/tex]

Factor each parentheses:

[tex]\implies u(u-1)-4(u-1)[/tex]

Factor out common term [tex](u-1)[/tex]:

[tex]\implies (u-1)(u-4)[/tex]

Substitute back [tex]u=x^2[/tex] :

[tex]\implies (x^2-1)(x^2-4)[/tex]

Factor both parentheses using the Difference of Two Squares: [tex]a^2-b^2=(a+b)(a-b)[/tex]

[tex]\implies (x+1)(x-1)(x+2)(x-2)[/tex]

Therefore, the factorisation of [tex]x^4-5x^2+4[/tex] is

[tex](x+1)(x-1)(x+2)(x-2)[/tex]

How many apples could you buy if you went to the store with five dollars? *

Answers

Answer:

depends on how much the apples cost

It really much depends on the type of apple and it’s price

pls help ill give a hundred points. select the correct answer from the drop down menu A(1,3),B(5,3),and D(1,-2) are three vertices of rectangle ABCD the coordinates of vertex C are select from the drop down menu (5,2),(-5,1),(5,-2),(2, -5)

Answers

Question ↷

A(1,3),B(5,3),and D(1,-2) are three vertices of rectangle ABCD the coordinates of vertex C are select from the drop down menu (5,2),(-5,1),(5,-2),(2, -5)

Answer↷

(5,-2)

Solution ↷

we know that,

the midpoint of the diagonals of a rectangle bisect each other,

so,

MP of AC = MP of BD

[tex] \huge \rightarrow \frac{x + 1}{2},\frac{y+ 3}{2} = \frac{5 + 1}{2},\frac{3 - 2}{2} \\ [/tex]

[tex] \huge \rightarrow \: x = 5 \: \\ \huge \rightarrow \: y = - 2[/tex]

Answer:

(5,-2)

Step-by-step explanation:

Cause me smart

2. 38, 42, 77, 47, 74, 51, 48, 41, 82, 72, 74, 129 Median: Q1 Q1: IQR: Outliers: ​

Answers

Answer: Heyo! ;D

I think I know how to solve this...

Let me know it this helps out in any way. :D

Median: "To find the median, first you need to list them in order from least to greatest:"

38, 41, 42, 47, 48, 51, 72, 74, 74, 77, 82, 129

"Now, you count starting from both ends and count to the middle. In this case, 51 and 72 are both the medians. However, there can be only one remaining median. So, what we do is add 51 to 72, then divide the sum by 2 to end with the correct median:"

72 + 51 = 123

123 / 2 = 61.5

Outliers: "All are in a pattern, beside the one number that stands out as the outlier in the given list of numbers. 129 is the only number that isn't in sync with the pattern, hence meaning this is the outlier in the sequence of numbers above."

~Artastic~

A small theater had 6 rows of 24 chairs each. Workers just removed 7 of these chairs. How many chairs are left? chairs

Answers

6 x 24 = 144
144 - 7 = 137
There is 137 chairs left in the theater. Hope this helps!

Answer:

137 chairs

Step-by-step explanation:

6*24=144.

144-7=137.

please mark as brainliest.

Which rate does not belong with the other three?Explain
8 pounds for every 2 feet
12 pounds peer 3 feet
20 pounds per 4 feet
24 pounds for every 6 feet

Answers

Answer:

The rate "20 pounds per 4 feet", doesn't belong with the other three because you get "5 pounds per foot" for the unit rate and for the other three, you get "4 pound per foot" for the unit rate.

Step-by-step explanation:

Unit rate = How much of something per 1 unit of something else

We write this as a ratio with a denominator of one

In this case, we are using "pound per foot"

1. "8 pounds for every 2 feet"

You can find the unit rate by dividing the first term of the ratio by the second term

[tex]\mathrm{\dfrac{ 8\:pounds }{ 2\:feet }}[/tex]

Simplify

[tex]\mathrm{4\:pounds}[/tex]

Unit rate = 4 pounds per foot

2. "12 pounds per 3 feet"

First, write the rate as a fraction

[tex]\mathrm{\dfrac{ 12\:pounds }{ 3\:feet }}[/tex]

Next, divide the numerator and denominator by 3

[tex]\mathrm{\dfrac{ 12\:pounds \div 3 }{ 3\:feet \div 3 }}[/tex]

Lastly, simplify and turn the denominator equal to 1

[tex]\mathrm{\dfrac{ 4\:pounds }{ 1\:foot }}[/tex]

Unit rate = 4 pounds per foot

3. "20 pounds per 4 feet"

First, write the rate as a fraction

[tex]\mathrm{\dfrac{ 20\:pounds }{ 4\:feet }}[/tex]

Next, divide the numerator and denominator by 4

[tex]\mathrm{\dfrac{ 20\:pounds \div 4 }{ 4\:feet \div 4 }}[/tex]

Lastly, simplify and turn the denominator equal to 1

[tex]\mathrm{\dfrac{ 5\:pounds }{ 1\:foot }}[/tex]

Unit rate = 5 pounds per foot

4. "24 pounds for every 6 feet"

You can find the unit rate by dividing the first term of the ratio by the second term

[tex]\mathrm{\dfrac{ 24\:pounds }{ 6\:feet }}[/tex]

Simplify

[tex]\mathrm{4\:pounds}[/tex]

Unit rate = 4 pounds per foot

The rate that doesn't belong is "20 pounds per 4 feet"

Algebra Complete the table.Write the
expression that can be used to find the
missing value in the second row.

Answers

Step-by-step explanation:

In the second column, we can see that every value of n is being added by 6.

Thus, the expression is n + 6.

Now, let's substitute the value of n in each column to verify each column. Then, using the expression, let's find the value of n + 6 where n = 28.

When n is 12:

n + 6 = 1812 + 6 = 1818 = 18

When n is 15:

n + 6 = 2115 + 6 = 2121 = 21

When n is 21:

n + 6 = 2721 + 6 = 2727 = 27

Thus, the expression is proven correct. Now, let's find n + 6 when n is 28.

Finding n + 6 when n is 28:

n + 6 = x28 + 6 = x34 = x

Thus, the missing value in the table is 34.

10 Cecelia took 40 minutes to complete a journey. She travelled half the distance at a speed of 100 km/h and the other half at 60 km/h. How far was her journey?

Answers

40 min = 40/60 hr = 2/3 hr

Distance = x km

t=distance/speed

x/200+x/120=2/3

multiply by 6oo

3x+5x=400

8x=400

x = 400/8=50km

The journey is for 50km


pls giive brainliest\

A globe has a diameter of 12 inches. It fits inside a cube-shaped box that has a side length of 12 inches.

​What is the volume, rounded to the nearest hundredth of a cubic inch, of the space inside the box that is not taken up by the globe?

Answers

The volume, rounded to the nearest hundredth of a cubic inch, of the space inside the box that is not taken up by the globe is 823.68 inches³

Volume of a sphere

The globe is a sphere. Therefore, the volume is as follows:

volume = 4 / 3 πr³

where

r = 12  /2 = 6 inches

volume = 4 / 3 × π × 6³

volume = 864 / 3 π

volume = 288 × 3.14  = 904.32inches³

Volume of a cube

The box is a cube. Therefore,

volume = L³

where

L = length

Therefore,

volume = 12³

volume = 1728 inches³

Therefore, the volume of the space inside the box that is not taken up by the globe is as follows:

volume not taken up = 1728 - 904.32 = 823.68 inches³

learn more on volume here: https://brainly.com/question/15385003

How many solutions are there for the quadratic equation?
Y=x^2+12x+36

Show work

Answers

Answer:

1 solution

x = -6

Explanation:

[tex]\rightarrow \sf y=x^2+12x+36[/tex]

[tex]\rightarrow \sf x^2+12x+36=0[/tex]

[tex]\rightarrow \sf x^2+6x+6x+36=0[/tex]

[tex]\rightarrow \sf x(x+6)+6(x+6)=0[/tex]

[tex]\rightarrow \sf (x+6)(x+6)=0[/tex]

[tex]\rightarrow \sf x=-6[/tex]

Hence there is only one solution for this quadratic equation and the value is -6

[tex]\\ \rm\rightarrowtail x^2+12x+36=0[/tex]

[tex]\\ \rm\rightarrowtail x^2+6x+6x+36=0[/tex]

[tex]\\ \rm\rightarrowtail (x+6)(x+6)=0[/tex]

Only one solution present

x=-6

Aiden has 15 pieces of candy in a brown paper bag. 3 are candy bars, 2 are gum, 4 are mints, 5 are chewy candies and 1 is a lollipop. What is the probability that he reaches in, grabs a candy bar or chewy candy, eats it and then grabs a piece of gum?



When typing in your answer, enter it as a fraction, such as 1/2. Simplify your answer.

8/?

Answers

Answer: 3/10

Step-by-step explanation: so you add 15+3+2+4+5+1 and that is 30 then you simplify 30 and get 3/10

Probability of candy bar 1/5
Probability of chewy candy 1/3
Probability of piece of gums 2/15

The probability of an event happening is given as 0.45
What is the probability of the event NOT happening?

Answers

Given:

⇒ Probability of happening of an event = 45%

To Find:

⇒ Probability of event

Now, probability of happening of an event is 45% means non happening event is 100 - 45 = 55%.

⇒ Probability of happening event = 45/100

⇒ Probability of happening event = 0.45

⇒ Probability of non happening event = 55/100

⇒ Probability of non happening event = 0.55

Hence, the correct option is (c) 0.45.

Extra Info:

Probability is the likelihood /chances of a given event's occurence which is expressed as a number between 1 and 0.

please solve 5/4+( -4 1/3)=?

Answers

Step-by-step explanation:

[tex] \frac{5}{4} + ( - 4 \times \frac{1}{ 3} ) \\ \\ \frac{5}{4} - \frac{4}{3} \\ \\ \\ \frac{15 - 16}{12} \\ \\ \frac{1}{12 } [/tex]

Lillian walked 5 miles in 3 hours. What was her walking rate in miles per hour?
3

Answers

Answer:

5/3

Step-by-step explanation:

Given:

5 miles per 3 hours

The question:

Rate formatted in miles per hour.

Which would be:-

5 miles per 3 hours

= 5/3

please help
what is the equation for the following graph

A=1

Answers

Answer:

[tex]f(x)=\sqrt{x+5}-3[/tex]

Step-by-step explanation:

Given function for graph: [tex]f(x)=\sqrt{x-h}+k[/tex]

Therefore, the parent function is [tex]f(x)=\sqrt{x}[/tex]

[tex]f(x)=\sqrt{x-h}+k[/tex] can be obtained by translating [tex]f(x)=\sqrt{x}[/tex] to [tex]h[/tex] units to the right and [tex]k[/tex] units up

The x and y intercept of [tex]f(x)=\sqrt{x}[/tex] is the origin

Therefore, this graph has been translated 5 units to the left and 3 units down.

Therefore, [tex]h=-5[/tex] and [tex]k=-3[/tex]

Substituting these values into the given function:

[tex]\implies f(x)=\sqrt{x-(-5)}+(-3)[/tex]

[tex]\implies f(x)=\sqrt{x+5}-3[/tex]

The morse code is "FOUR BEFORE DECIMAL" I need help with the math problem and how FOUR BEFORE DECIMAL fits into it

Answers

Answer:

the answer is 113.5

Step-by-step explanation:

rate brainliest!

Answer:

114

Step-by-step explanation:

3^5 = 243

4^2 = 16

(243 - 16) / (4 + (-2))

227/2 = 113.5

I think that the morse code phrase refers to rounding the answer

which comes to be...

114

Therefore the 4 is before the decimal

I am not entirely sure, but that is what I think it is

PLEASE RATE!! I hope this helps!!

If you have any questions comment below

Help help help please !!!!

No LINKS !!!

Answers

Answer:

$55,200

Step-by-step explanation:

Area of yard = length * breadth

So,

Area = 50*46 = 2300 sq. feet

Again,

Cost per sq. feet = $24

So, For 2300 sq. feet,

Total cost = $24*2300 = $55,200

Hope it helped!

in right triangle ABC, line CD is perpendicular to line AB, AD=9 cm DB=16 cm. Find CD and the area of triangle ABC

Answers

Answer:

8+8

Step-by-step explanation:

the answer to the whats C and D well c=8 and D=8

A plumber charges $25 to come to a home, and $15 per hour for a repair. Which equation gives the total cost, y, for a repair that lasts x hours?

Answers

Answer:

15x + 25 = y

Step-by-step explanation:

$25 is a fixed cost and will have to be paid if the plumber comes and $15 times the number of hours it takes to do the repair is the variable cost. 'x' in this case is the number of hours. So the equation will be 15x + 25 = y

Which of the following represent lengths of the sides of a
right triangle?
Select all that apply.
A 4,5,6
B 8, 15, 17
C 10, 15, 20
D
5, 12, 13

Answers

B and D because 8^2+15^2=17^2 and 5^2+12^2=13^2

Directions: Select all correct answers.

Select all situation representing independent events.

Question 7 options:


Spinning spinner two times.


Rolling a die and then flipping a coin.


Taking one candy out of a bag of candies, eating it, and then taking another candy.


Taking a card from a set of ten cards, replacing it, and then, taking another card.


Taking a sock from a drawer, placing it on your foot, and then picking another sock from the drawer.


Taking a card from a set of ten card, not replacing it, and then taking another card.

Answers

Answer:

Step-by-step explanation:

I just need help with Part C

Answers

the domain is simply the values that "t" or the independent variable can safely take whilst not producing any extraneous values.

well, the context from the table is that it starts at time of 10 days and goes on to the 40th day, so "t" starts off at 10 and ends at 40, well, that is the domain in context, [10 , 40].

Please help! will give brainlest! locks in 30 min!

Answers

Answer:

LAST CHOICE IS THE ANSWER.

Step-by-step explanation:

#BRAINLIESTBUNCH

Answer:

[tex]-\sqrt{3}[/tex]

Step-by-step explanation:

tan (θ) = [tex]-\frac{\sqrt{3} }{2}[/tex] ÷ [tex]\frac{1}{2}[/tex]

tan (θ) = [tex]-\sqrt{3}[/tex]

hope this helps and is right!! p.s. i really need brainliest :)

SHORT EASY QUESTION PLS HELP)

Find the exact volume if the radius is 7 inches and the height is 18 inches.

Answers

Answer:

V≈2770.88

Step-by-step explanation:

The radious is 7 inches, that means the diameter is 14 inches.

The height is 18 inches. so...

V=πr2h=π·72·18≈2770.88472

So hence, your answer is

V≈2770.88

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Have a great day!

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