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Effectus [21]
3 years ago
11

After releasing of radioactive material into.The atnosphere from.A nuclear.Powe plant in a country in 1988, the hay in that coun

try was contaminayed by radioactive.Isotope remains, how long did the famers need to.Wait to use this hay
Mathematics
1 answer:
Radda [10]3 years ago
4 0

Answer:

the question is incomplete, so I looked for a similar one:

<em>After the release of radioactive material into the atmosphere  from a nuclear power plant, the hay was contaminated by iodine  131 ( half-life, 8 days). If it is all right to feed the hay to cows  when 10% of the iodine 131 remains, how long did the farmers  need to wait to use this hay? </em>

iodine's half life (we are given x, we need to find b):

0.5A₀ = A₀eᵇˣ

x = 8 days

we eliminate A₀ from both sides

0.5 = eᵇ⁸

ln 0.5 = ln eᵇ⁸

-0.69315 = b8

b = -0.69315 / 8 = -0.08664

since the farmers need to wait until only 10% of the iodine remains (we already calculated b, now we need to find x):

0.1A₀ = A₀eᵇˣ

0.1 = eᵇˣ

ln 0.1 = bx

where b = -0.08664

x = ln 0.1 / -0.08664  = -2.302585 / -0.08664  = 26.58 days

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Then the reflex angle will be measured by the formula (360-x)
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3 0
3 years ago
I need help with this one.
Mandarinka [93]

Answer:

T_{n} = \frac{1}{5} T_{n-1} with T₁ = 5000

Step-by-step explanation:

There is a common ratio r between consecutive terms in the sequence, that is

r = \frac{1000}{5000} = \frac{200}{1000} = \frac{40}{200} = \frac{1}{5}

This indicates the sequence is geometric with recursive rule

T_{n} = r T_{n-1}

Here tr = \frac{1}{5} , thus

T_{n} = \frac{1}{5} T_{n-1} , T₁ = 5000

3 0
3 years ago
Which equation represents a proportional relationship? A. y = x + 1 3 y=x+13 B. y = 1 − 1 3 x y=1-13x C. y = 3 x + 1 3 y=3x+13 D
34kurt

Answer:

Option D. y=\frac{1}{3}x

Step-by-step explanation:

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form y/x=k or y=kx

In a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin

<u><em>Verify each case</em></u>

case A) we have

y=x+\frac{1}{3}

Remember that

the line must pass through the origin

so

For x=0, y=0

In this case

For x=0

y=0+\frac{1}{3}=\frac{1}{3}

so

The line not passes through the origin

therefore

The equation A not represent a proportional relationship

case B) we have

y=1-\frac{1}{3}x

Remember that

the line must pass through the origin

so

For x=0, y=0

In this case

For x=0

y=1-\frac{1}{3}(0)=1

so

The line not passes through the origin

therefore

The equation B not represent a proportional relationship

case C) we have

y=3x+\frac{1}{3}

Remember that

the line must pass through the origin

so

For x=0, y=0

In this case

For x=0

y=3(0)+\frac{1}{3}=\frac{1}{3}

so

The line not passes through the origin

therefore

The equation C not represent a proportional relationship

case D) we have

y=\frac{1}{3}x

Remember that

the line must pass through the origin

so

For x=0, y=0

In this case

For x=0

y=\frac{1}{3}(0)=0

so

The line passes through the origin

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The equation D represent a proportional relationship

3 0
3 years ago
Which of these is true?
Furkat [3]

Answer:

C

Step-by-step explanation:

Tell me if you need or want an explanation

5 0
3 years ago
I WILL GIVE 20 POINTS TO THOSE WHO ANSWER THIS QUESTION RIGHT NOOOO SCAMS AND EXPLAIN WHY THAT IS THE ANSWER
Step2247 [10]

Answer:

A = 297\pi

Step-by-step explanation:

To solve this problem we need to be familiar with the formula for the surface area of a cone:

A = \pi r(r + \sqrt{h^2+r^2})

We are given the length of a side and the diameter, to calculate the radius divide the diameter in half:

r = \frac{d}{2}\\r = \frac{18}{2}\\r = 9 cm

To calculate the height of the cone, we must use the Pythagorean Theorem:

C^2 = A^2 + B^2

We can treat the side length as the hypotenuse C, the radius as the base A, and solve for height B. Set the expression up like this:

C^2 = A^2 + B^2\\24^2 = 9^2 + B^2\\B^2 = 24^2 - 9^2\\B = \sqrt{24^2 - 9^2}\\B = \sqrt{576 - 81}\\B = \sqrt{495}\\B \approx 22.25

Now we can plug into our original formula:

A = \pi r(r + \sqrt{h^2+r^2})\\A = \pi 9(9+\sqrt{\sqrt{495}^2+9^2}\\A = \pi 9(9+\sqrt{495 + 81}\\A = \pi 9(9+\sqrt{576})\\A = \pi 9(9 + 24)\\A = \pi 9(33)\\A = 297\pi

5 0
2 years ago
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