The half-life of radium is 1690 years. If 80 grams are present now, how much will be present in 870 years?
grams

Answers

Answer 1

Answer:

A(t) = amount remaining in t years

= A0ekt, where A0 is the initial amount and k is a constant to be determined.

Since A(1690) = (1/2)A0 and A0 = 80,

we have 40 = 80e1690k

1/2 = e1690k

ln(1/2) = 1690k

k = -0.0004

So, A(t) = 80e-0.0004t

Therefore, A(430) = 80e-0.0004(430)

= 80e-0.172

≈ 67.4 g

Step-by-step explanation:

hope it helpful for you ❤️


Related Questions

What is negative 10 divided by .22

Answers

Answer:

That would be negative 45 or - 45

Please correct me if im wrong

I need help! Does anyone understand?

Answers

Answer:

the answer should be G or H

find the slope from the pair of the points
(-3,-4) (1,5)

Answers

Answer:

2.25

Step-by-step explanation:

m = 9 / 4 = 2.25

points belong to an increasing, linear function.

Equation: y = 2.25x + 2.75.

BRAINLIEST?

What is 1/3÷1/2 math answers?

Answers

Step-by-step explanation:

If you like my answer than please mark me brainliest thanks

Given A(-4-5), B(8,-1), C (-5, 9), and D (2,8) determine whether AB is parallel,
perpendicular, or neither to CD

Answers

Answer:

neither

Step-by-step explanation:

If 2 lines are parallel then their slopes are equal

If 2 lines are perpendicular then the product of their slopes = - 1

Calculate the slopes m using the slope formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = A (- 4, - 5 ) and (x₂, y₂ ) = B (8, - 1 )

[tex]m_{AB}[/tex] = [tex]\frac{-1-(-5)}{8-(-4)}[/tex] = [tex]\frac{-1+5}{8+4}[/tex] = [tex]\frac{4}{12}[/tex] = [tex]\frac{1}{3}[/tex]

Repeat

with (x₁, y₁ ) = C (- 5, 9 ) and (x₂, y₂ ) = D (2, 8 )

[tex]m_{CD}[/tex] = [tex]\frac{8-9}{2-(-5)}[/tex] = [tex]\frac{-1}{2+5}[/tex] = - [tex]\frac{1}{7}[/tex]

The slopes are neither equal nor have a product of - 1

escape resort rents snowshoes in the winter the resort changes charges seven dollars per day and a flat fee of three dollars to cover cleaning right in equation that shows how the cost why depends on the length of the rental and days X do not include $in the equation

Answers

Answer:

Y=7x+3

Step-by-step explanation:

A parabola can be drawn given a focus of (1,-3) and a directrix of x=9, what can be said about the parabola?

Answers

Check the picture below.

well, we can say that since its directrix is a vertical line, the parabola opens horizontally, the focus point is at the left of the directrix thus it opens leftwards, ithas a vertex at (5,-3), recall that the vertex is half-way between the focus point and the directrix.

What is the equation for the line in slope-intercept form?

Answers

Y=-8/2x+5
Hgfxdffggggujjcfccchhjbvg

negative seven times a number is negative two hundred forty five. what is the number?



pleasee i need help

Answers

Answer:

35

Step-by-step explanation:

since i couldn't answer before

arrange the given the decimals in ascending order from least to greatest ​

Answers

To arrange in ascending order means to arrange numbers from the smallest value to the greatest value in the set of numbers provided.

9) 3.021 < 3.12 < 3.121 < 3.21

Look at the 1st decimal place after the point first. 0 is less than 2 & 1, so 3.021 is the least number. Now, for 3.12 & 3.121, look at the 3rd place. 3.12 = 3.120, so it’s smaller than 3.121. Then comes 3.21 which is the greatest number in this set.

10) 5.0090 < 5.05 < 5.059 < 5.5

Here, 5.0090 is the smallest number. Then comes 5.05 = 5.050 which is smaller than 5.059. 5.5 is the greatest number.

_________

RainbowSalt2222 ☔

math question!!!!!!!!!!!

Answers

Answer:

A: Walking

Step-by-step explanation:

-It cannot be biking because the constant of proportionality (COP) is 9.5 miles (per hour).

-It cannot be running because the COP is 5 miles (per hour).

-It cannot be swimming because the COP is 4.5 miles (per hour).

he is walking

14 divided by 4 is equivalent to 3.5 the equation being 14/4=3.5 or 3 1/2

Will give brainliest if helpful and correct

Answers

Answer:

(-2, -1.5)

Step-by-step explanation:

hope this helps!

The temperature in antartica is 20 degrees below freezing at night. During the day, the temperature increases
by 30 degrees. What is the daytime temperature?

Answers

Answer:

42

Step-by-step explanation:

In a certain chemical the ratio of zinc to copper is 4 to 15. A jar of the chemical contains 345 of copper how many grams of zinc does it contain ?

Answers

Answer:

92.

Step-by-step explanation:

By proportion the mass of zinc = (345/ 15) * 4

= 92.

Change 41/7 from an improper fraction to a mixed number.

Answers

Answer:

5 6/7

Step-by-step explanation:

how many times does 7 go onto 41?

7 x 5 = 35

remainder is 6 so;

5 6/7

Hey there!

41/7

= (5 * 7 + 6)/7

= (5 * 7)/7 + 6/7

= 5 6/7

= 5 6/7 ≈ 41/7

Therefore, your answer is: 5 6/7

Good luck on your assignment and enjoy your day’

~Amphitrite1040:)

Help pls I have no clue what this is

Answers

Answer:

  b = 76°

Step-by-step explanation:

Angle JIK is the smaller acute angle in one of four congruent right triangles. Angle GHK is the larger acute angle in those triangles, marked as 60°. The sum of the acute angles in a right triangle is 90°, so you have ...

  60° +(b-46)° = 90°

  14° +b = 90° . . . . . . . simplify

  b = 76° . . . . . . . subtract 14°

A) y = 5x

B) y = 10x

C) y = 7.5x

D) y = 30x​

Answers

Y=30x is the answer to this

can someone help with this

Answers

Step-by-step explanation:

A. n is the number of persons excluding chaperones

B. The equation describes the situation where the total admission cost at orchard A is equal to that of B. (This happens at n=17 persons)

C. For which number of persons is orchard A cheaper than orchard B? (It will be for n is more than 17 persons, but there is no requirement to calculate this).

a simple random sample of 60 items resulted in a sample mean of 80.

Answers

Answer:

(c) The effect of a larger sample size on the margin of error is that the margin of error will increase.

Step-by-step explanation:

The scale for a map to actual distance is 2 centimeters to 100 miles. The driving distance on the map between Los Angeles and Las Vegas is 5.4 centimeters. What is the actual distance, in miles, between Los Angeles and Las Vegas?

Answers

[tex]\begin{array}{ccll} \stackrel{cm}{map}&\stackrel{mi}{actual}\\ \cline{1-2} 2&100\\ 5.4&x \end{array}\implies \cfrac{2}{5.2}=\cfrac{100}{x}\implies 2x = 520\implies x = \cfrac{520}{2}\implies x = 260[/tex]

One non-negative number is the reciprocal of another number. The sum of the two numbers is a minimum. What are the two numbers

Answers

The two numbers are 1 and 1.

Let the non-negative number be x and its reciprocal be y = 1/x

The sum of the two numbers is f(x,y) = x + y

= x + 1/x

= f(x)

For f(x) to be minimum, we differentiate it with respect to x and equate it to zero to find the value of x at which irt is minimum.

So, df(x)/dx = d(x + 1/x)/dx

= dx/dx + d(1/x)/dx

= 1 - 1/x²

Equating it to zero, we have

1 - 1/x² = 0

1 = 1/x²

x² = 1

Taking square-root of both sides, we have

x = ±√1

x = ±1

Since x is non-negative x = + 1

We differentiate f(x) again to determine if this value gives a minimum for f(x).

So, d²f(x)/dx² = d(1 - 1/x²)/dx

= d1/dx - d(1/x²)/dx

= 0 - × (-2/x³)

= 2/x³

Substituting x = 1 into the equation,

d²f(x)/dx² = 2/x³

= 2/1³

= 2 > 0.

So x = 1 is a minimum point for f(x)

Since x = 1 and y = 1/x, y = 1/1 = 1

So, the two numbers are 1 and 1.

Learn more about sum of two numbers here:

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a 25 -ft ladder rests against the side of a house. the distance between the top of the lader and the ground is 17 ft more than the distance between the base od the ladder and the bottom of the house. find both distances. ​

Answers

Answer:

Step-by-step explanation:

x² + (x + 17)² = 25²

x² + x² + 34x + 289 = 625

2x² + 34x - 336 = 0

x² + 17x - 168 = 0

x = (-17 ±√(17² - 4(1)(-168))) / (2(1))

x = 7 or - 24   the negative distance makes no sense, but if we plug our good answer of 7 ft in for the base length, the height comes out to be + 24 ft

base = 7 ft

height = 24 ft

An internet service provider (ISP) has experienced rapid growth in the past five years. As part of its marketing strategy, the company promises fast connections dependable service. To achieve its objectives, the company constantly evaluates the capacity of its servers. One component of its evaluation is an analysis of the average amount of time a customer is connected and actively using the Internet daily. A random sample of 12 customer records shows the following daily usage times, in minutes.
274 347 283 307 327 314
303 285 280 391 359 325
Interpret the confidence interval estimate.
a. Based on the sample data, with 90% confidence, the ISP can conclude that the sample mean daily usage time is between _____ minute(s) and _____ minute(s).
b. Based on the sample data, with 90% confidence, the ISP can conclude that the true population mean daily usage time is between _____ minute(s) and _____ minute(s).
c. Based on the sample data, the ISP can conclude that 90% of daily usage times are between _____ minute(s) and _____ minute(s).

Answers

Using the t-distribution, it is found that the correct interpretation is:

b. Based on the sample data, with 90% confidence, the ISP can conclude that the true population mean daily usage time is between 297.75 minute(s) and 334.75 minute(s).

We can find the standard deviation for the sample, which is why the t-distribution is used to solve this question.

We are given a   sample size of [tex]n = 64[/tex].

Using a calculator, we find that:

The sample mean is [tex]\overline{x} = 316.25[/tex]The sample standard deviation is [tex]s = 35.68[/tex]

The confidence interval is:

[tex]\overline{x} \pm t\frac{s}{\sqrt{n}}[/tex]

The critical value, using a t-distribution calculator, for a two-tailed 90% confidence interval, with 12 - 1 = 11 df, is t = 1.7959.

Then:

[tex]\overline{x} - t\frac{s}{\sqrt{n}} = 316.25 - 1.7959\frac{35.68}{\sqrt{12}} = 297.75[/tex]

[tex]\overline{x} + t\frac{s}{\sqrt{n}} = 316.25 + 1.7959\frac{35.68}{\sqrt{12}} = 334.75[/tex]

From the confidence interval, we can infer about the population mean, hence, the correct option is:

b. Based on the sample data, with 90% confidence, the ISP can conclude that the true population mean daily usage time is between 297.75 minute(s) and 334.75 minute(s).

A similar problem is given at https://brainly.com/question/15180581

How many numbers are prime between 40 and 50?

Answers

Step-by-step explanation:

Correct answer:

(The primes between 40 and 50 are 41, 43, and 47 - three.

The two legs of a right triangle are and . The hypotenuse is . Solve for in terms of the other variables.
What's the answer I'm very confused.

Answers

Answer:

the answer is c

Step-by-step explanation:

u welcome

The value of r in terms of other variables in the given right triangle using the Pythagoras theorem can be shown as r = √(t² - s²).

What is the Pythagoras Theorem?

According to the Pythagoras Theorem, in a right triangle, the square of the hypotenuse is equal to the sum of the squares of the legs.

How to solve the question?

In the question, we are shown a right triangle with the hypotenuse as t, and the legs as r and s.

We are asked to solve for r in terms of other variables.

By Pythagoras theorem in the given right triangle, we can say that:

r² + s² = t², which is the required equation.

To solve for r in terms of other variables, we do as follows:

r² + s² = t²,

or, r² + s² - s² = t² - s² {Subtracting s² from both sides of the equation},

or, r² = t² - s² {Simplifying},

or, r = √(t² - s²) {Square rooting both sides of the equation}.

Thus, the value of r in terms of other variables in the given right triangle using the Pythagoras theorem can be shown as r = √(t² - s²).

Learn more about the Pythagoras theorem at

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#SPJ2

If 1,600 divided by n = 4, what is the value of n?
A 40
B 400
C4,000
D40,000

Answers

Answer:

B) 400

Step-by-step explanation:

To find the value of n, you would have to divide 1600 by 4. 1600/4=400.

Answer:

400

Step-by-step explanation:

1600 4

One thousand dollars is deposited into an ordinary annuity after each 6 month period for 2 years. The account pays 4 percent interest compounded semiannually.what is the future value of the account in 2 years ??

Answers

Answer:

  $4121.61

Step-by-step explanation:

Use the formula for the balance of an ordinary annuity.

  A = P((1 +r/n)^(nt) -1)/(r/n)

  A = $1000((1 +.04/2)^(2·2) -1)/(.04/2) ≈ $4121.61

The future value of the account is $4121.61.

Can someone please help me

Answers

Answer:

question 10

14×50= 700 pages

Triangles FEG and FDH are similar. If segment DH is 28 units, what is the
measure of segment EG?

Answers

28 units i think. Since they are similar

The quotient of b and -6 is 18

Answers

The quotient is the result obtained by dividing one quantity by another.

This means that b/-6 = 18

b = 18*-6

b = -108

Answer:

b = -108

Step-by-step explanation:

Given the mathematical expression, "The quotient of b and -6 is 18":

We could represent the given mathematical expression as follows:

b ÷ -6 = 18  or   [tex]\frac{b}{-6} = 18[/tex] .

In the fraction form, [tex]\frac{b}{-6} = 18[/tex] , multiply both sides by -6 to eliminate the denominator on the left-hand side. It will also isolate b:

[tex]\frac{b}{-6} = 18[/tex]

[tex](-6)(\frac{b}{-6}) = 18(-6)[/tex]

b = -108

In order to double-check whether we have the correct value for b, simply substitute its vlaue into the equation:

[tex]\frac{-108}{-6} = 18[/tex]

18 = 18 (True statement).  

The value of b = -108, hence, the quotient of -108 and -6 is 18.  

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