Pleas help I am brainliesting

Answer:

The wood was cut approximately 8679 years ago.

Step-by-step explanation:

At first we assume that examination occured in 2020. The decay of radioactive isotopes are represented by the following ordinary differential equation:

[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dm}{dt}[/tex] - First derivative of mass in time, measured in miligrams per year.

[tex]\tau[/tex] - Time constant, measured in years.

[tex]m[/tex] - Mass of the radioactive isotope, measured in miligrams.

Now we obtain the solution of this differential equation:

[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]

[tex]\ln m = -\frac{1}{\tau} + C[/tex]

[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Where:

[tex]m_{o}[/tex] - Initial mass of isotope, measured in miligrams.

[tex]t[/tex] - Time, measured in years.

And time is cleared within the equation:

[tex]t = -\tau \cdot \ln \left[\frac{m(t)}{m_{o}} \right][/tex]

Then, time constant can be found as a function of half-life:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)

If we know that [tex]t_{1/2} = 5730\,yr[/tex] and [tex]\frac{m(t)}{m_{o}} = 0.35[/tex], then:

[tex]\tau = \frac{5730\,yr}{\ln 2}[/tex]

[tex]\tau \approx 8266.643\,yr[/tex]

[tex]t = -(8266.643\,yr)\cdot \ln 0.35[/tex]

[tex]t \approx 8678.505\,yr[/tex]

The wood was cut approximately 8679 years ago.

Answer: so the answer is A

Step-by-step explanation: -3/2

if you ever have a question like that again go to Math-way it is every helpful and easy.

Step-by-step explanation:

The order of the numbers doesn't matter, so we'll use combinations instead of permutations.  The number of combinations is:

₄₅C₈ = 215,553,195

So the probability of a ticket having the winning combination is 1 / 215,553,195.

The expected value to the state is:

E(X) = 10,000 (1) ($2) + 10,000 (1 / 215,553,195) (-$1,000,000)

E(X) = $19954

The expected value to you is:

E(X) = 10,000 (1) (-$2) + 10,000 (1 / 215,553,195) ($1,000,000)

E(X) = -$19954

Answer:

9.8427x10⁴

Step-by-step explanation:

Answer:

98427x^2

9.8427x10^4

Step-by-step explanation:

Answer:

no solution (parallel lines )=1/1=1/1=5/1

Step-by-step explanation:

Answer:

-132/5

Step-by-step explanation:

-4(2x+13) + 3x = 80

-8x - 52 + 3x = 80

-5x = 80+52

5x = -132

x = -132/5

Feel free to mark this as brainliest! :D

Answer:

width = 15 ft

length = 18 ft

Step-by-step explanation:

lets assume the width is w, and length is l.

For the first equation, we all know that a rectangle is 2 widths and 2 lengths added up, which in "math" language looks like this:

2w+2l= 66

for the second equation, the problem says that the length is 3 ft greater than the width. From there, we can derive the equation:

w+3 = l

Now you can substitute one of the variables, length or width, but it is easier to do length. The equation ends up being:

2(w+3) + 2w = 66

Distributive property:

2w+6+2w = 66

which is equal to:

4w+6 = 66

which finally is:

w=15 ft.

Now that we know the width, we can just add 3 to the width to get the length, according to the problem. You get:

L = 18 ft.

Answer:

40

Step-by-step explanation:

Working backwards, he has to get 140 from working hours alone. 140/3.5=40. He has to work 40 hours to get at least 165

10/4  if its right also have a good my dude

Answer:

about 37.31 inches of space

Step-by-step explanation:

In this case, you would need to find the area of a cylinder with these dimensions.

Formula: 2πrh+2πr²

The r is the radius, and since the diameter in this situation would be 2.5, the radius would be 1.25.

2π(1.25)(3.5)+2π(1.25)²

2π4.375+2π1.5625

8.75π+3.125π

37.3064128

about 37.31 inches of space

Answer:

A. 1 in. = 22.5 mi

Step-by-step explanation:

Since 22.5 x 10 = 225, we can conclude that this will fit the scale needed. B. is incorrect because it is simply illogical in context with a scale and the question. C. is incorrect since 10 x 0.04 is 0.4, which does not equal 10. D. is incorrect since we need the scale to add up to equal 225 mi, not 22.5.

Hope this helps!

Answer

4

Step-by-step explanation:

Add 9 to 11, then divide that by 5.

Answer:

4

Step-by-step explanation:

work backwards 11+9 is 20. Divide 20 by 5 = 4

Answer:

21.715 degrees.

Step-by-step explanation:

There are 14 vertexes (vertices) for a 14-gon. It is 'regular' so all these angles are equal. So the exterior angle of each is 180-154.285 = 21.715 degrees.

you should just have to times the yards by three like the second one is 12

Answer:

2x

Step-by-step explanation:

You're dividing 14 multiplied by a number by 7 multiplied by a number. So you'd get 2 multiplied by a number.

Answer:

[tex]10^3=1,000[/tex]

Step-by-step explanation:

The expression 10=1,000 is obviously false, but we can make it true by rewriting it with an exponent.

Note that 1,000=10*10*10

Or, equivalently:

[tex]1,000=10^3[/tex]

Thus, if we modify the original false expression and add an exponent 3 to the base 10, then it would be true:

Original:

10=1,000 => false

Rewritten true:

[tex]\boxed{10^3=1,000}[/tex]

Answer:

22.82

Step-by-step explanation:

can u plz mark me as brainliest??

Answer:

22.82

Step-by-step explanation:

3.1*1.4 = 4.34

27.16-4.34 = 22.82

[edited, I messed up the order of operations before, sorry]

Answer:

Step-by-step explanation:

Data

speed v1=8mph

speed v2=3mph

distance= 1.25

time t=?

speed= distance/time

distance=speed*time

1.25=8*t-3*t

1.25=8t-3t

1.25=5t

t=1.25/5

t=0.25hours

In minutes it is 15min

Answer:

Yes it appropriate to use the normal approximation to find the probability that more than 43% of the people in the sample have high blood pressure

Step-by-step explanation:

From the question we are told that

The population proportion is  p=0.4

  The sample size is  n =  39

  The sample proportion is  [tex]\^ p = 0.43[/tex]

Generally for normal approximation to be used

       [tex]np > 10[/tex]

so np  =  39 * 0.4 =  15.6 > 10

   and [tex]n(1- p) > 10[/tex]

so   n(1-p ) = 39(1-0.4) = 23.4 >10

Given that the both condition is meet it mean that  it appropriate to use the normal approximation to find the probability that more than 43% of the people in the sample have high blood pressure

Answer:

Y=2x-1

Step-by-step explanation:

In order to find the slope, its rise over run. So you would move from (0,-1) to the next point it intercepts, (1,1) and find it from there

As for the Y-Intercept, it would just be wherever the line connects with the Y axis, which happens to be (0,-1) or Negative 1.

Answer:

x=3

y=5

because 5-2=3 so 3 is x

and 2+3 is 5 so y is 5

Answer:

X = 3, Y =

Step-by-step explanation:

This is because 2+3=5,

and5-3=2

Answer:

where's the map

Step-by-step explanation:

Answer:

x=25

Step-by-step explanation:

First, we add all like terms. Then, we solve for x.

[tex]70+x + 55 + 30 = 180\\x+70 + 55 + 30 = 180\\x+155=180\\x=25[/tex]

We can rearrange some things because order does not matter with addition. Next, we just use basic equation solving techniques.

Answer:

25. Hope this helps :)

Step-by-step explanation:

180-70=110

110-55=55

55-30=25

Your missing answer would be 25

X=25

Answer:

a. -14

b. -13

c. -5

d. -3

e. -12

f. 0

Step-by-step explanation:

hope it helps

Answer:

A is -14.

B is -13

C is -5

D is -3

E is -12

F is 0

Step-by-step explanation:

A, B, E both numbers are negative so you just add them together and add a negative sign.

C would read 4-9

D 10-7 and add a - to the answer

F is 6-6

Answer:

2020

Step-by-step explanation:

101 • 21 = 2121

2121 - 101 = 2020

Answer:

8/15

Step-by-step explanation:

-4/5 ÷ -3/2

Copy dot flip

-4/5 * -2/3

Multiply the numerators

8

Multiply the denominators

15

Put the numerator over the denominator

8/15

Answer: 8/15

Step-by-step explanation: (-4/5)divided by (3/-2) is 8/15.

Answer:

C. -2n² - n + 5

Step-by-step explanation:

In expression C, the coefficient of the n term is -1;

  The expression in choice C is given as:

               -2n² - n + 5

The coefficient is the number before a variable;

  For n², the coefficient is -2

    for n, the coefficient is -1