A lab currently has 70 mg of radioactive material that decays at 3.5% per year. Federal regulation for the substance says that the material must be safely stored until it reaches its half-life, at which time the material can be disposed.

How many years will the lab have to safely

store the material before disposal?

Answers

Answer 1

Answer:

The lab will have to wait 19.45 yers to safely store the material before disposal.

Step-by-step explanation:

Exponential equation for substance decay:

A exponential equation for the amount of a substance after t years is given by:

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

In which A(0) is the initial amount and r is the decay rate, as a decimal.

Decays at 3.5% per year.

This means that [tex]r = 0.035[/tex]

So

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

[tex]A(t) = A(0)(0.965)^{t}[/tex]

How many years will the lab have to safely store the material before disposal?

It needs to reach half-life, that is, t for which A(t) = 0.5A(0). So

[tex]A(t) = A(0)(0.965)^{t}[/tex]

[tex]0.5A(0) = A(0)(0.965)^{t}[/tex]

[tex](0.965)^t = 0.5[/tex]

[tex]\log{(0.965)^t} = \log{0.5}[/tex]

[tex]t\log{0.965} = \log{0.5}[/tex]

[tex]t = \frac{\log{0.5}}{\log{0.965}}[/tex]

[tex]t = 19.45[/tex]

The lab will have to wait 19.45 yers to safely store the material before disposal.


Related Questions

A carpenter is putting a skylight in a roof. If the roof measures 10 + 8 by 8 + 6 and the skylight measures + 5 by 3 + 4, what is the area of the remaining roof after the skylight is built?
a. 77^2 + 115 + 68
b. 77^2 + 105 + 28
c. 83^2 + 115 + 68
d. 77^2 − 105 + 28

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Yea what the other girl said

PLEASE ANSWER ASAP WILL GIVE BRAINLIEST

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The mean should be 10
10 is the mean I’m pretty sure

In ΔDEF, the measure of ∠F=90°, the measure of ∠D=69°, and FD = 64 feet. Find the length of DE to the nearest tenth of a foot.

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Answer:

Step-by-step explanation:

can u do this plz urgent ​

Answers

Answer:

1. Area = 22cm square cm 2. Area = 9m square m 3. Area = 18m square mHope it help ♥ heart and vote po plz..

Kim bought her Supreme shoes for $52 on eBay. She marks up the shoes to resell on GOAT for 120% of the price.



a) What is the amount of markup? $




b) What is the price of the shoes after markup? $

Answers

A) $10.40
B) $62.40
hope this helps!!

Answer:

a) $10.4

b) $62.4

Step-by-step explanation:

a) What is the amount of markup? $

$52 - 100%

$X   - 120%

100X = 52*120

100X = 6240

X = 6240/100

X = $62.4

62.4-52=

$10.4  

b) What is the price of the shoes after markup? $

$62.4

the difference of 4 and 5 times h ​

Answers

Answer:

4-5h

Step-by-step explanation:

difference = minus sign

and 5 times h

Answer:

Step-by-step explanation:

There are two answers to this making the question slightly ambiguous.

1) 4 - 5*h

2) (4 - 5)*h

It is impossible to tell which answer is the correct one. However, if I had to guess, I would say it is 4-5*h

Pls help me
I really need help so I can not go through summer school pls

Answers

4 i think sorry if i’m wrong

Using L Hospital's rule, evaluate :
lim
x →0(x² – Sin²x)/x^2​

Answers

Answer:

0

Step-by-step explanation:

L Hospital's rule states that as long as u have the form

of infinity / infinity or 0/0 in general you can take its derivative to find the limit.

In this case as X tends to 0, the numerator tends to 0

Denominator will also tends to 0.

We have the 0 / 0 form, which means we can take the derivative for its numerator and denominator which gives

(2x - 2SinxCosx) / 2x | lim x -> 0

= (2x - Sin2x) / 2x | lim x -> 0

Based on this equation, as x tends to 0

both numerator and denominator tends to 0.

So we take its second derivative,

(2 - 2Cos2x) / 2

Now as x -> 0,

we will get (2 - 2)/2 = 0

2 2/5 - 1 1/3 + 3 1/2=​

Answers

Answer:

16.2

Step-by-step explanation:

I think it is the answer. not sure

If I’m correct, the decimal form is 4.6. The improper fraction is 23/5. And when the fraction is mixed, the answer is 4 3/5

what is the leading coefficient of 5z^5-2z^6+z

Answers

Answer:

3

Step-by-step explanation:

3(x - 2) – 2x + 3 = -12

Answers

Answer:

hii

Step-by-step explanation:

3(x-2)-2x+3=-12

3 times x = 3x

3 times -2 = -6

3x-6-2x+3=-12

3x + 2x = 5x

-6 + 3 =-3

i don't know the rest I'm sorry

Which option best shows X ≤ -3

Answers

Step-by-step explanation:

the answer is b because the circle is filled with color as it should be and shows that x is equally to number 3 too

Answer:

yep, it's b.

Step-by-step explanation:

a line with a closed circle means that it's less than or equal to.

HELP PLZ and thank you

find the measure of the arc or central angle indicated. assume that lines which appear to be diameters are actual diameters.

Answers

Answer:

Step-by-step explanation:

Circle degrees total 360 .  

360 - 126 -54-54 (other side of vertical angles) equals 126 degrees left for the other two remaining sections.  

14x+4  +15x+6 =126

19x+10 = 126

29x = 116

x=4 .  answer .

calculate the volume of a liquid with a density of 5.45g/km and a mass of 65g ​

Answers

Answer:

11.93 ml

rounded to two significant figures: 12ml

Step-by-step explanation:

65/5.45=11.93 ml

Please mark me as brainliest

−4.5=−0.5(x−7.1)

solve for x and teach me how to give brainliest

Answers

-4.5 = -0.5 (x - 7.1)

-4.5 = -0.5x + 3.55
-3.55 -3.55
——————————
-8.05 = -0.5x
———————
-0.5

X = 16.1

is -1 equivalent to -3 - (-12)

Answers

Answer:

no

Step-by-step explanation:

-1 - (-12)

the two negative signs before the 12 cancel out so it ends up being

-1+12

-1+12=11

11 and -1 are not equal to each other

Answer:

No

Step-by-step explanation:

-3-(-12)=-3+12

-3+12=9

Caroline can ride her bike 5 miles in 25 minutes. At this rate, how long would it take her to bike 8 miles?

Answers

Answer:

40 min.

Step-by-step explanation:

5/25=1/5

1/5=0.2

8/0.2=40

Answer:

40 mins

Step-by-step explanation:

do 25 divided by 5 and you get 5, which means she can ride one mile in 5 mins, so then multiply 5 and 8 and you get the product of 40.

Which equation could be solved using this application of the quadratic formula? x = (- 3 plus/minus sqrt(3 ^ 2 - 4(1) * (24)))/(2(1)) A. x ^ 2 + 6x + 24 = 3x B 3x ^ 2 + 3x + 24 = 3 C. x ^ 2 + 3x - 24 = 3 D x ^ 2 + 3x + 24 = 3

Answers

Answer:

[tex]x^2 + 3x + 24 = 0[/tex]

Step-by-step explanation:

Given

[tex]x = \frac{-3\±\sqrt{3^2 - 4*1*24}}{2*1}[/tex]

Required

Select equation with the above solution

The solution is represented as:

[tex]x = \frac{-b\±\sqrt{b^2 - 4ac}}{2a}[/tex]

By comparison:

[tex]b= 3[/tex]       [tex]a = 1[/tex]       [tex]c = 24[/tex]

So, the equation is:

[tex]ax^2 + bx + c = 0[/tex]

[tex]x^2 + 3x + 24 = 0[/tex]

PLS HELP!!

What is the volume, in cubic centimeters, of a cube with an edge length of 15
centimeters?

Answers

Answer:

3375

Step-by-step explanation:

The formula for volume is

volume = length x height x width

or in simpler terms (only works for cubes i think)

v = a^3

so we know that the side is 15cm long, so we substitute that back into the equation, so,

3375 = 15 x 15 x 15

or

3375 = 15^3

I hope that this helps you out :)

Helps please is for now

Answers

Answer:

(-3,5) and (2,3). That's the answer. Plug this number and it would be fine

Sasha saved $28.34 in November and $39.57 in December. By the end of
January, she wants to have saved $100. How much money does she need
to save in the month of January? Make sure to include your work, number
sentences, and your answer with words.

Answers

Answer:

$32.09

Step-by-step explanation:

It's $32.09 because, 39.57-28.34=67.91. And 100-67.91= 32.09. Goodluck!

What is 0.5 (0.1)(1/2)

Answers

Answer:

0.025

Step-by-step explanation:

-5n = 15
show your work

Answers

Answer: 15 divided by -5 = -3

Answer:

n=-3

Step-by-step explanation:

divide both sides

-5n/(-5)=15/(-5)

divide both sides

n=15/(-5)

n=-3

Pls help me due in 20 minutes.

Answers

Answer:

A and D; she needs 1/12 cups of corn

Step-by-step explanation:

What should be placed in the box to make the equation true?

Answers

Answer:

2x^4

Step-by-step explanation:

When multiplying variables with exponents multiply the coefficients (the number before the variable) and add the exponents.

SO to solve you have to find a number that when multiplied by 32 equals 64 and a number when added to 8 gives you 12.

2*32=64

8+4=12

So the answer is 2x^4

If this helped please consider giving brainliest.

5/6 minus (- 3/4)
HELP PLS

Answers

Answer:

In order to solve this problem, you have to find the lowest common denominator.  Take multiples of both 6 and 4 and see which is the lowest you have in common.

4: 4, 8, 12, 16, 20

6: 6, 12, 18, 24

So 12 is the lowest common multiple....

5/6 x ?/? = ?/12 (you have to multiply the numerator and the denominator by the same number)

3/4 x ?/? = ?/12 (you have to multiply the numerator and the denominator by the same number)

When the denominators are the same, you can subtract the numerators.  The denominator will stay 12!

Step-by-step explanation:

YAY! I want a brain

Answer:

Exact Form: 19/12

Decimal form:1.583

Mixed number form: 1 7/12

Step-by-step explanation:

hope i was right!

4,000 as a product of power of 10

Answers

Answer:

4,000 to the tenth power is 1.045876E36

Step-by-step explanation:

Find the slope of the line passing through the points (-2,-2) and (6,-2).
slope

Answers

Answer:

0/8

Step-by-step explanation:

Slope equals y 2 minus y 1 divided by x 2 minus x 1

-2-(-2)/6-(-2)

0/8

can someone help me with this?​

Answers

Answer:

$79.38

Step-by-step explanation:

First find the area of the parallelogram: b*h

= 8.1* 3.5

= 28.35 square meters

now multiply by the cost (2.80) by 28.35 to get the final answer: 79.38

If 2x+y=16 and 4x-y, find the value of x and y​

Answers

Answer:

Step-by-step explanation:

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