A radioactive material is known to decay at a yearly rate proportional to the amount at each moment. There were 1000 grams of the material 10 years ago. There are 980 prams right now. What will be the amount of the material right after 20 years?
a. 10 ln 2/ln(1000/980)
b. 10^6/980
c. 980^3/10^6
d. 980^2/10^3

Answers

Answer 1

Answer:

Amount left is 941.95 g.

Step-by-step explanation:

initial amount = 1000 g

time = 10 years

amount left =  980 grams

Now

[tex]980 = 1000 e^{-\lambda t}\\\\e^{\lambda\times 10}= 1.02\\\\10 \lambda = ln 1.02\\\\\lambda = 1.98\times10^{-3} per year[/tex]

time t = 20 years

Let the amount is N.

[tex]980 = 1000 e^{-\lambda t}\\\\e^{\lambda\times 10}= 1.02\\\\10 \lambda = ln 1.02\\\\\lambda = 1.98\times10^{-3} per year\\N = 980 e^{- 1.98\times 10^{-3}\times 20}\\\\ln N = ln 980 - 0.0396\\\\ln N = 6.88 - 0.0396 = 6.86\\\\N = 941.95 g[/tex]


Related Questions


Robert owns two dogs. Each day, one dog eats
1/6 of a scoop of dog food and the other dog eats br
1/6 of a scoop. Together, how much dog food do
the two dogs eat each day? Write in simplest
form.

Answers

Answer:

1/3

Step-by-step explanation:

1) 1/6+1/6= 2/6

2) 2 and 6 can both be divide be 2.

   2/2=1 and 6/2=3

7th grade math!!! Please help!! will mark brainlist ​

Answers

The answer is the first choice. If every 2 cm. is 4 cm., that means that the dimensions' values are doubled. Then, you can just double the dimensions. Preferably, in my opinion, this is the easier way to go. By your preference, though, you can do it the longer way as well.

There are 4 2s in the number 8.

There are 3 2s in the number 6.

If each of the 2s are 4s,

So, therefore,

Transforming the 2s to 4s,

4x4=16 cm.

3x4=12 cm.

So, this means that the final answer is the first choice. I hoped that this helped  answer your question. Enjoy your day, and take care!

Answer:

`Length=16 feet, width=12 feet

Image result for how to  use scale model step by step'

Divide the real life dimension of either length or width by that of the model. So the real life object had a length of 32m, and the model had a length of 8, then do 8(4). This is equal to 32, then divide by 2.

Hope this helps love <3

PLEASE HELP i’ll give brainliest to best and correct answer

Answers

Step-by-step explanation:

|- 9| + |- 3|

9 + 3

12

I hope this answers your question

If the Miller's spend $1200 on housing each month, then what is their total monthly budget?

Answers

Answer:

2400$

Step-by-step explanation:

Miller's Family spends 50% of their budget on housing and we know that they spent 1200$ this month, so 1200$*2 = 2400$.

Have a nice day! :-)

the x coordinates of the point where 2y-x=10 intersect the line y=3x​

Answers

Answer:

5

Step-by-step explanation:

2y=10+x

y=3x

Equalizing both sides:

10+x=3x

10=3x-x

10=2x

x=5

Can someone help me out

Answers

Answer:

236m^2

Step-by-step explanation:

8x5=40x2=80

6x5=30x2=60

6x8=48x2=96

80+60+96=236

what us 10 to the power of two​

Answers

the answer is

10² ( ten square )

step by step :

10² = 10 × 10

= 100

Answer: 100

Step-by-step explanation: 10*10=100

2. Mandla spent one quarter of his pocket money on sweets. a. What fraction does he have left? b. If he had R40 pocket money, how much did he spend?​

Answers

Answer:

a. 3/4 of pocket money left

b. R10

Step-by-step explanation:

a. 4/4 - 1/4 = 3/4

b. 40/4 = 10 = 1/4 of pocket money

(a). The fraction of pocket money left is 3/4

(b). If he had R40 pocket money, he spend R10.

What is the Ratio?

The ratio is defined as a relationship between two quantities, it is expressed one divided by the other.

What are Arithmetic operations?

Arithmetic operations can also be specified by the subtract, divide, and multiply built-in functions.

The operator that perform arithmetic operation are called arithmetic operators .

Operators which let do basic mathematical calculation

+ Addition operation : Adds values on either side of the operator.

For example 4 + 2 = 6

- Subtraction operation : Subtracts right hand operand from left hand operand.

for example 4 -2 = 2

* Multiplication operation : Multiplies values on either side of the operator

For example 4*2 = 8

Mandla spent one-quarter of his pocket money on sweets

Let x be the total amount of pocket money Mandla had originally

Solution of (a).

⇒ x - (1/4)x

⇒ (3/4)x

The fraction of pocket money left = 3/4

Solution of (b).

1/4 of pocket money

⇒ (1/4)x

⇒ (1/4)40

10

Learn more about Ratio here:

brainly.com/question/1504221

#SPJ2

(7 points) for the given diagram, it is known that e is the midpoint of ad and bc. use this information to prove that triangle aec= triangle deb. each congruence or ewuality and statement must be accompanied by a reason
PLS HELP

Answers

Given:

E is the midpoint of AD and BC.

To prove:

[tex]\Delta AEC\cong DEB[/tex]

Proof:

Statement                                                    Reason

1. E is the midpoint of AD and BC            1. Given

2. [tex]AE\cong DE[/tex]                                              2. Definition of midpoint

3. [tex]CE\cong BE[/tex]                                              3. Definition of midpoint

4. [tex]\angle AEC\cong \angle DEB[/tex]                                    4. Vertically opposite angle

5. [tex]\triangle AEC\cong \triangle DEB[/tex]                                   5. SAS congruence postulate

Hence proved.

Next question
lets keep going

Answers

Answer:

U = 67.6 degrees

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

cos U = adj side / hypotenuse

cos U = sqrt(10)/ sqrt(69)

cos U = sqrt(10/69)

Taking the inverse cos of each side

cos ^-1( cos U) =  cos ^-1(sqrt(10/69))

U = 67.62335

To the nearest tenth

U = 67.6 degrees

Step-by-step explanation:

here's the answer to your question

You have $90,000 in cash. You can deposit it today in a mutual fund earning 7.5
percent semiannually; or you can wait, enjoy some of it, and invest $12,000 in your
brother's business after two years. Your brother is promising you a return of at least 12
percent on your investment. Whichever alternative you choose, you will need to cash
in at the end of 8 years. Assume your brother is trustworthy and that both investments
carry the same risk. Which one will you choose?

Answers

I will go to the Bahamas instead and think about later

A parallelogram is made up of a rectangle with a base of 12 centimeters (cm) and a height of 5 cm, and two triangles, each with a base of 2 cm and height of 5 cm. Jeremy calculates the area of the parallelogram by multiplying the base and height of the rectangle to get 60 cm2.
Is Jeremy's answer correct? Why or why not?

Select the option that correctly answers both questions.

No, he forgot to multiply by 12 when calculating the area of the rectangle.

Yes, he correctly calculated the area of the parallelogram as b⋅h.

No, he forgot to add the area of the triangles to the area of the rectangle.

Yes, he correctly calculated the area of the parallelogram as 12bh.

Answers

No, he forgot to add the area of the triangles to the area of the rectangle.

It is said that Jeremy thought he solved for the area of the whole parallelogram correctly by multiplying the base and height of the rectangle, which is just a part of the whole parallelogram.

Jeremy’s answer is incomplete, he only calculated the area of the triangle as the answer.

This is because one way of finding an area of a parallelogram is dividing the shape into a rectangle with a triangle on each side.

The real area of the parallelogram is 70 cm^2
(with areas of each triangles added)

With that being said, the formula of a parallelogram that is said is:
A = bh
Which means a height perpendicular to the base of the whole paralleogram.

Your small business spent $40 on food and another $60 on materials. Then, you sold an item for $120, but you had to pay a $90 service fee. Finally, you were given a refund from the Internal Revenue Service (IRS) for $70. If the expression describing these transactions is the following, then how does it evaluate?

Answers

Answer:

40$+60$=100$ spent

120$sold

90$ payed

70$ refund

120 (sold) -90 (payed) =30+70 (refund) =100$ (profit)

Step-by-step explanation:

You spent 100$

And you sold and got 120 but you payed 90$ from 120$ money left is 30$

Then they refunded you (pay back the money (give you the money ))

So the money that your left with is 30$ and the refund money is 70$

So add the money that your left with is gives you 100$

How many solutions does the nonlinear system of equations graphed below have?
A. Four
B. Two
C. One
D. Zero​

Answers

Answer:

Option (A)

Step-by-step explanation:

Solution of two functions represented by the graph are the common points or point of intersection of the graphs.

From the graph attached,

Parabola and ellipse are intersecting each other at four points.

Therefore, solutions of the given non linear functions will be FOUR.

Option (A) will be the correct option.

Find the perimeter of the image below

Answers

Permittee image below find of

Find the missing ? Step by step need it

Answers

Answer:

30 degrees

Step-by-step explanation:

Use the Tan formula.

Choose all the numbers that are multiples of 2.
A 18
B. 21
C. 34
D. 45
E 50
F. 67
G. 83

Answers

Answer:

18 , 34and 50 are multiples of 2

Step-by-step explanation:

2×9=18

17×2=34

25×2=50

Answer:

A,C,E

Step-by-step explanation:

A,9×2=18

C,17×2=34

E,25×2=50

I need help ASAP ????!!!!

Answers

Answer:

Step-by-step explanation:

Amplitude 2

wave height 4

trough 5

crest 3

wave length 1

The acute angle of the right angle triangle are in the ratio of 4:5​

Answers

Answer:

Since the triangle is a right angled triangle, one of the angles is 90°. In the right angled triangle, the acute angles are in the ratio 4:5. Let the measures of the acute angles of the triangle in degrees be 4k and 5k, where k is a constant.

Step-by-step explanation:

hope it helps.

Answer:

40and50

Step-by-step explanation:

let the acute angles be 4x and 5x then,

4x+5x+90=180 [sum of all angles of a right angled triangle]

or,9x=180-90

or,x=90/9

x=10

4x=4×10=40

5x=5×10=50

solve for x please help!

Answers

Answer:

x = -1/4

Step-by-step explanation:

-4(-5x-3) = 7

Distribute

20x +12 = 7

Subtract 12 from each side

20x+12-12 = 7-12

20x = -5

Divide by 20

20x/20 = -5/20

x = -1/4

Answer:

x = -0.25

Step-by-step explanation:

-4(-5x - 3) = 7

Step 1. Multiply -4 by the numbers in parentheses (negative number x negative number = positive number)

20x + 12 = 7

Step 2. Subtract 12 from both sides

20x = -5

Step 3. Isolate the variable

x = -5/20

x = -0.25
••••••••••••••••••••••••••••••••
doomdabomb: All brainliest
and thanks are appreciated
and would mean a lot to me,
Thanks!

Which of the following graphs is the same as y = log12X?

Answers

Answer:

Step-by-step explanation:

5 năm trước tổng số tuổi của hai mẹ con là 55 tuổi. Hiện nay tuổi con bằng 4/9 lần tuổi mẹ. Tính số tuổi của mẹ và tuổi con hiện nay?

Answers

Answer:

12

Step-by-step explanation:

12

Suppose we flip two fair coins. Let X be the random variable that indicates the number of heads that come up. Let Y be the random variable that indicates the number of tails that come up. Show that X and Y are not independent.

Answers

Answer:

I doubt it is not going to be a great day of school

Maggie's brother is 6 years younger than four times her age. The sum of their ages is
59.
How old is Maggie?
Maggie is
years old.

Answers

Answer:

Maggie is 11 years old

Step-by-step explanation:

let m be Maggie and b be her brother.

[tex]m+b=59[/tex]

[tex]b=4m-6[/tex]

substitute for b.

[tex]m+4m-6=59[/tex]

[tex]5m-6=59[/tex]

add 6 to both sides

[tex]5m=55[/tex]

divide by 5 on both sides

[tex]m=11[/tex]

double check by finding the brother's age by substituting for m

[tex]11+b=59[/tex]

[tex]b=48[/tex]

What is an equation of the line that passes through the points (-1, 6) and
(-1, -5)?

Answers

Answer:

x = -1

Step-by-step explanation:

Because the line passes through two points that both have the same x value, this means the line is vertical, and the slope is undefined.

So the equation of the line is x = -1.

Find mABC.
A. 102°
B. 54°
C. 14°
D. 78°

Answers

By the supplementary angles theorem, we know that both of the angles add up to equal 180°, so:

(4x + 22) + (8x - 10) = 180

12x + 12 = 180

12x = 168

x = 14

Now you just have to plug in x into the value for ∠ABC:

∠ABC = 4x + 22

∠ABC = 4(14) + 22

∠ABC = 46 + 22

∠ABC = 68°

Answer:

D = 78

Step-by-step explanation:

The two angles form a straight line so they add to 180

4x+22 + 8x-10 = 180

Combine like terms

12x +12 =180

Subtract 12 from each side

12x+12-12 = 180-12

12x = 168

Divide by 12

12x/12 =168/12

x=14

We want to find ABC

4x+22 = 4*14+22 = 56+22 = 78

dùng tiền gửi ngân hàng trả tiền cho người bán 100.000.000

Answers

Answer:

Sorry, i dont know

Step-by-step explanation:

I dont know the answer to this question.....

Which equation has the same solution as 10(x) - x + 5 = 41

Answers

Step-by-step explanation:

if that is truly the full problem description, then we have

10x - x + 5 = 41

=>

9x = 36

our simply

x = 4

so, I am not sure, what your teacher wants to see as result.

there is an infinite number of equations I could find, all with the solution x = 4.

how many number of three different digit less than 500 can be formed from the integer 123456​

Answers

Answer:

80 numbers

Step-by-step explanation:

(6 - 2(because when the hundreds is 5 or 6, it will higher than 500)) x 5 x 4 = 80

Old machine: 8.2, 8.0, 7.9, 7.9, 8.5, 7.9, 8.1,8.1, 8.2, 7.9
New machine: 8.0, 8.1, 8.0, 8.1, 7.9, 8.0, 7.9, 8.0, 8.1

Use a 0.05 significance level to test the claim that the volumes of Bubbly Beverage filled by the old machine vary more than the volumes of juice filled by the new machine.

Answers

Answer:

We Reject the Null, H0 and conclude that the volume of juice filled by old machine varies more than volume filled by new machine

Step-by-step explanation:

Given the data:

Old machine: 8.2, 8.0, 7.9, 7.9, 8.5, 7.9, 8.1,8.1, 8.2, 7.9

Sample size, n = 10

Using calculator :

s1² = 0.37889.

New machine: 8.0, 8.1, 8.0, 8.1, 7.9, 8.0, 7.9, 8.0, 8.1

Sample size, n = 9

s2² = 0.006111

Hypothesis :

H0 : s1² = s2²

H1 : s1² > s2²

New machine :

s2² = 0.006111 ; n = 9

Using the Ftest :

Ftest statistic = larger sample variance / smaller sample variance

Ftest statistic = 0.37889 / 0.006111

Ftest statistic = 62.0

Decision region :

Reject H0 ; If Test statistic > Critical value

The FCritical value at 0.05

DFnumerator = 10 - 1 = 9

DFdenominator = 9 - 1 = 8

Fcritical(0.05, 9, 8) = 3.388

Since 62 > 3.388 ; Reject H0 and conclude that volume filled by old machine varies more than volume filled by new machine

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