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 3.8 days. The initial amount of radon used in an experiment is 75 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 N in terms of t.
b. How much gas radon approximately remains after 3.8 days?
c. approximately when will the amount of radon remaining be 10 grams?

Answers

Answer 1

Using an exponential function, it is found that:

a) [tex]N(t) = 75(0.5)^{\frac{t}{3.8}}[/tex]

b) 37.5 grams of the gas remains after 3.8 days.

c) The amount remaining will be of 10 grams after approximately 11 days.

What is an exponential function?

A decaying exponential function is modeled by:

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

In which:

A(0) is the initial value.r is the decay rate, as a decimal.

Item a:

We start with 75 grams, and then work with a half-life of 3.8 days, hence the amount after t daus is given by:

[tex]N(t) = 75(0.5)^{\frac{t}{3.8}}[/tex]

Item b:

This is N when t = 3.8, hence:

[tex]N(t) = 75(0.5)^{\frac{3.8}{3.8}} = 37.5[/tex]

37.5 grams of the gas remains after 3.8 days.

Item c:

This is t for which N(t) = 10, hence:

[tex]N(t) = 75(0.5)^{\frac{t}{3.8}}[/tex]

[tex]10 = 75(0.5)^{\frac{t}{3.8}}[/tex]

[tex](0.5)^{\frac{t}{3.8}} = \frac{10}{75}[/tex]

[tex]\log{(0.5)^{\frac{t}{3.8}}} = \log{\frac{10}{75}}[/tex]

[tex]\frac{t}{3.8}\log{0.5} = \log{\frac{10}{75}}[/tex]

[tex]t = 3.8\frac{\log{\frac{10}{75}}}{\log{0.5}}[/tex]

[tex]t \approx 11[/tex]

The amount remaining will be of 10 grams after approximately 11 days.

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Related Questions

Write an equation to represent the following statement. The product of 7 and j is 91. Solve for j. j​

Answers

Answer:

13

Step-by-step explanation:

7j=91

91/7=j

13

hope that helps:)

7. An arched window has dimensions as
shown at the right. Consider the top of the
window to be a semicircle. How much plastic
covering is needed to cover the window,
following the outline of the window?

Answers

The amount of plastic covering needed to cover the window is 25.71.

How much plastic covering is needed?

The window consists of a semi circle and a rectangle. The circumference and the perimeter of the semi circle and a rectangle has to be determined.

Circumference of the semi circle = 1/2πd + d

Where:

π = 3.14

d = diameter = 3

1/2 x 3.14 x 3 + 3 = 7.71

Perimeter of the rectangle = 2(length + width)

2x (6 + 3) = 18

18 + 7.71 = 25.71

Please find attached an image of the window. To learn more about the perimeter of a rectangle, please check: https://brainly.com/question/3205029

Evaluate the following expression: (2,3)-3(1,1). Enter your answer as a vector

Answers

Answer:

Step-by-step explanation:

An expression is defined as a set of numbers, variables, and mathematical operations. The value of the given expression(2,3) - 3(1,1) in vector form is (-1, 0).

What is an Expression?

In mathematics, an expression is defined as a set of numbers, variables, and mathematical operations formed according to rules dependent on the context.

What is subtraction?

Subtraction is a mathematical operation that reflects the removal of things from a collection. The negative symbol represents subtraction.

The given expression can be solved as shown below.

(2,3) - 3(1,1)

Multiply 3 in the second vector,

= (2,3) - (3,3)

Subtracting vectors

= (2-3, 3-3)

= (-1, 0)

Hence, the value of the given expression(2,3) - 3(1,1) in vector form is (-1, 0).

Learn more about Expression:

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#SPJ5

Find the GCF for the set of numbers.

18, 36, and 60

Answers

Step-by-step explanation:

Factors of 36 are {1,2,3,4,6,9,12,18,36}

.

Factors of 60 are {1,2,3,4,5,6,10,12,15,20,30,60}

Common factors are }1,2,3,4,6,12} .

greatest Common Factor is 12 .

how do I simplify this expression
3x+4+2x+7

Answers

Step-by-step explanation:

3x + 4 + 2x +7

= 3x + 2x + 4 + 7

= 5x + 11

Each patron can borrow up to 6 books. If all the patrons are currently holding on to 6 books each, how many books are left in the library?

Answers

Answer:

Your answer would be:
3,384 books are left in the library

If each patron has 6 books, and there are 564 patrons:

564 x 6 = 3,384 books left

In conclusion, there are 3,384 books left in the library.





Step-by-step explanation:

Have a great rest of your day
#TheWizzer

Lucy bought 4 pairs of pants for $21.79 each. She paid the cashier using as few $20 bills as necessary. How much change did she receive?

Answers

The amount of change Lucy receives if she paid with few $20 bills is $12.84

How to find amount of change to receive

Cost of each pair of pants = $21.79Number of pairs of pants = 4

Total cost of pants = $21.79 × 4

= $87.16

Amount paid to the cashier = few $20 bills

If the total cost of the pants exceeds $80, then she paid with 5 $20 bills

5 $20 bills = $100

Her change = $100 - $87.16

= $12.84

Learn more about cost:

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Starting at an initial height of 364 feet, an object is projected
upward at 60 feet per second. In how many seconds will it
reach the ground? I’m

Answers

Step-by-step explanation:

4.5 s, 324 ft

Explanation:

The object is projected upward with an initial velocity of

v_0 = 144 ft/sv

0

=144ft/s

The equation that describes its height at time t is

s(t) = -16t^2 + 144 ts(t)=−16t

2

+144t (1)

where t, the time, is measured in seconds.

In order to find the time it takes for the object to reach the maximum height, we must find an expression for its velocity at time t, which can be found by calculating the derivative of the position, s(t):

v(t) = s'(t) = -32t +144v(t)=s

(t)=−32t+144 (2)

At the maximum heigth, the vertical velocity is zero:

v(t) = 0

Substituting into the equation above, we find the corresponding time at which the object reaches the maximum height:

\begin{gathered}0=-32t+144\\t=\frac{144}{32}=4.5 s\end{gathered}

0=−32t+144

t=

32

144

=4.5s

And by substituting this value into eq.(1), we also find the maximum height:

s(t) = -16(4.5)^2+144(4.5)=324 fts(t)=−16(4.5)

2

+144(4.5)=324ft

used this way i even don't know sorry:))

What is the distance between (-2, 4) and (5, 4) on a coordinate grid?

Answers

Answer:

7 units

Step-by-step explanation:

(Background info, skip if not interested or needed for you)

The equation for distance on a cartesian plane coordinate system is based off the pythagorean theorem.

[tex]a^2 + b^2 = c^2[/tex]

a and b being sides of a right triangle, c being the hypotenuse.

When we are solving for distance we are solving for c essentially.

[tex]c[/tex] = [tex]\sqrt{a^2 + b^2}[/tex]

Because a and b are side lengths of the right triangle, we need to find a way to find that in terms of coordinates. So here we might say that a is equal to the horizontal distance between the 2 points or Δx, and we would say that b is the vertical distance between the 2 points Δy.

(solutions)

So essentially distance is:

[tex]d = \sqrt{(x_2 - x_1)^2+ (y_2-y_1)^2 }[/tex]

Now we just use the values given to us, and sub in the x and y values respectively.

(-2,4) [tex]x_1 = -2, y_1 = 4[/tex]

(5,4)[tex]x_2 = 5, y_2 = 4[/tex]

plug these values in:

[tex]d = \sqrt{((5) - (-2))^2+ (4-4)^2 } = \sqrt{(7)^2+ (0)^2 } = \sqrt{7^2 } = 7[/tex]

Therefore the distance is 7 units.

Evaluate the expression below for x = 2, y=-3, and z=-1.
x2 z2 - y2(x+z)
A. -23
B. -5
C. 13
D. 27

Answers

Answer:

It should be B

Step-by-step explanation:

2 2 -1 2 - -3 2 (2+-1)

1. Always do what's in parentheses

so we know that 1 is a negative and 2 is bigger than that number so you would just subtract normally.

2 2 -1 2 - -3 2 -1

Then get all exponents done.

4 -1 - 9-1

3-9-1

-6-1

Which should give u -5


How can we describe the relationships that exist between circles and lines?

Answers

circles are 360⁰ and lines are 180⁰

What is the solution to the system of equations?
y=2/3x+3
y = -2

Answers

Answer:

and

Step-by-step explanation:

we have

-----> equation A

------> equation B

we know that

The solution of the system of equations is equal to the intersection point of both graphs

Using a graphing tool  

see the attached figure

There are two intersection points

Therefore

The system of equations has two solutions

The solutions of the system of equations are the points  and

Find the missing value in the table
(Ignore all the writing I did already I think it’s wrong but I’m not sure)

Answers

Answer:

1.

+4

number: 11

2.

x × 3

number: 48

3.

+5

number 46

4.

÷2

number: 19

5.

-1.5

number: 19.5

6.

-0.2

number: 31.2

On average, Evie’s chicken lays 3 eggs every 15 days. At this rate, how many days will it take Evie’s chicken to lay 45 eggs?

Answers

Answer:

43 ffhfhfhfhfhfhchchchchchc

Answer:

It will take 225 days for Evie's chicken to lay 45 eggs

Step-by-step explanation:

Draw a number line to represent the street sign below

Answers

Its kind of like how it is on a car to tell how fast your going i hoped this helped!

what is the answer i need help

Answers

Answer:

[tex]588mm^3[/tex]

Step-by-step explanation:

Each side of the blue pyramid is 3 times the size of the red pyramid.

Instead of just dividing by 3 for the volume we must divide by 9 instead because we're working in cubes.

someone help me please​

Answers

wait a min Answer:

Step-by-step explanateion: it's í 4

What is the value of sin(80°)cos(20°) – cos(80°)sin(20°)?

Answers

The value of sin(80°)cos(20°) – cos(80°)sin(20°) using the trignometry property is √3/2.

What is difference formula in trignometry?

The difference formula in trignometry for the sine funciton is given as,

[tex]\sin(A-B)=\sin(A)\cos(B) -\cos(A)\sin(B)[/tex]

The trignometric equation given in the problem is,

[tex]\sin(80^o)\cos(20^o) -\cos(80^o)\sin(20^o)[/tex]

Compare this equation with the above eqution, we get,

[tex]A=80^o\\B=20^o[/tex]

Thus, this equation can be written as,

[tex]\sin(80^o)\cos(20^o) -\cos(80^o)\sin(20^o)=\sin(80-20)\\\sin(80^o)\cos(20^o) -\cos(80^o)\sin(20^o)=\sin(60)\\\sin(80^o)\cos(20^o) -\cos(80^o)\sin(20^o)=\dfrac{\sqrt{3}}{2}[/tex]

Hence, the value of sin(80°)cos(20°) – cos(80°)sin(20°) using the trignometry property is √3/2.

Learn more about the difference formula in trignometry here;

https://brainly.com/question/2142049

PLSSS HELP IF YOU TURLY KNOW THISS

Answers

Answer:

See below.

Step-by-step explanation:

The answer would be 2 3/4.

The third tick represents 3/4, and this is between 2 and 3.

-hope it helps

Answer:

My guess is 2 3/4

Step-by-step explanation:

Sorry if i'm wrong, if im right can i have brainliest? So explanation is that the plotted point on the number line is c so that will make the numerator is id.k the difference between them the top of the number would be three because c is ploted on c and id.k how to get 4.

(5.04×10^12)÷(6.3×10^9) in scientific notation

Answers

Answer:

i think the answer will be = 8 × 10^2

(5.04*10^12) / (6.3*10^9)= (5.04/6.3) *10^(12-9)
=0.8*10^3

What is the volume of a sphere with a radius of 6.9 ft, rounded to the nearest tenth of a cubic foot?

Answers

Answer:

1376.1 ft^3

Step-by-step explanation:

The volume of a sphere formula: V=4/3πr^3

r = 6.9 ft

V = 4/3 * π * (6.9^3) = 1,376.055

to the nearest tenth it's 1376.1 ft^3

Casey wanted to find the intercepts of the graph of the equation 10x+4y=20. He decided to put the equation in slope-intercept form first. Here is his work:

10x+4y=20
4y=20−10x
y=20−10x4
y=5−10x

He concluded that the slope is m=12 and the y-intercept is (0, 5).

What error did Casey make? Within your explanation, give the correct solved for y equation, the correct slope, and the correct y-intercept.

Answers

Answer:

made a mistake in step 3

Step-by-step explanation:

there, he should have gotten y=5-2x which is then translated to y=-2x+5

this means the y-intercept is correct, but the slope is actually -2

Which of the following is equivalent to : 3x + 6 + 2x + 2 + x
A. 5x + 8
B. 6x + 8
C. 14x

Answers

option b is correct, (b)6x+8

Find the next three terms of the sequence 2000 ,200, 20 … and write the term to term rule.​

Answers

Answer:

2 is the next number in the sequence

Step-by-step explanation:

in this pattern, you go down by one decimal spot ( zero)

this is a geometric sequence since there is a common ratio between each term.

which trig ratio
determine which trig ratio to use to solve for x

Answers

Answer:

sin = opp / hyp

cos = Adj / hyp

tan = opp / adj


7. cos 41 = x / 86

8. sin x = 5/13

9. cos x = 9/37

10. tan 61 = x/28

11. sin 41 = x/65

12. tan x = 79/84

Step-by-step explanation:

Write the log equation as an exponential equation. You do not need to solve for x.
In (3x + 2) = 3x

Answers

[tex]\ln(3x+2) = 3x\\\\\implies \log_e (3x+2) = 3x\\\\\implies e^{3x} = 3x+2[/tex]

Given triangle ABC is congruent to DEC find m

Answers

First, we know that angle B is congruent to angle E.

2x + 40 = 5x + 10

2x + 30 = 5x

30 = 3x

x = 10

Angle B and Angle E = 60 degrees

Angle C = 14 degrees

Remember that the interior angles of a triangle always add up to 180 degrees. Now that we know 2 of the 3 angles of these triangles, and because they are congruent, all that's left to do is find Angle A/D by setting up a simple equation.

60 + 14 + D = 180

74 + D = 180

D = 106

Angle D = 106 degrees

Hope this helps!

Answer:

Step-by-step explanation:

<E = <A                property of congruency.

<A = 5x + 10        Comes from the fact that <A and <E are equal.

Three angles of the triangle are given. They add to 180 degrees.

2x + 40 + x + 4 + 5x + 10 = 180         Combine like terms

8x + 54 = 180                                     Subtract 54 from both sides.

8x + 54 - 54 = 180 - 54                      Combine  

8x = 126                                              Divide by 8

8x/8 = 126/8

x = 15.75

<B = <D                                               Congruency and parallel lines

<D = 2x + 40                                       Substitute for x

<D = 2*15.75  +  40                             Combine

<D = 31.5 + 40

<D = 71.5

I need it as a linear function thank you

Answers

[tex]5~~,~~\stackrel{5(6)}{30}~~,~~\stackrel{30(6)}{180}~~,~~\stackrel{180(6)}{1080}~~,~~\stackrel{1080(6)}{6480}~\hfill \boxed{f(x)=x_{n-1}(6)}[/tex]

now, that's recursive, we can also write it in explicit as [tex]5(6)^x[/tex]

Find the 53rd multiple of 62, if the 54th multiple is 3348.

Answers

Answer:

[tex]\displaystyle 3286[/tex]

Explanation:

Just multiply 62 and 53 to get 3286.

I am joyous to assist you at any time.

the vertices of ABC are points A(1,1), B(4,1), and C(4,5). find the cosines of the angles of the triangle.

Answers

Answer:

cos(A) = 3/5cos(B) = 0cos(C) = 4/5

Step-by-step explanation:

The mnemonic SOH CAH TOA reminds you of the relation between the cosine of an angle and the sides of the triangle.

  Cos = Adjacent/Hypotenuse

__

Angle A

In the given triangle, the hypotenuse is AC. The side adjacent to angle A is AB, so its cosine is ...

  cos(A) = AB/AC

  cos(A) = 3/5

__

Angle B

The right angle in the triangle is angle B. The cosine of a right angle is 0.

  cos(B) = 0

__

Angle C

The side adjacent to angle C is CB, so its cosine is ...

  cos(C) = CB/AC

  cos(C) = 4/5

Answer:

cos <ABC=0

cos <BAC=3/5

cos<ACB=4/5

GIVE 5 STARS IF YOU DO RSM!!!

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