.
Radioactive Strontium The half-life of strontium-90 is 28 years. How long will it take a 50- mg sample to decay to a mass of 32 mg?

Answers

Answer 1

The time taken is obtained as 3 years.

What is the time taken?

We know that radioactivity has to do with the fact that a substances does disintegrate gradually over a period of time.

Let us recall the formula;

N/No = (1/2)^t/t1/2

N = The mass of radioactive atoms at time t

No = The mass of radioactive atoms initially present

t = time taken

t/12 = half life of the radioactive nucleus

Then;

32/50 = (1/2)^t/28

0.64 =  (1/2)^t/28

log 0.64 = t/28 log0.5

t/28 = log(0.64/0.5)

t = 28 * log(0.64/0.5)

t = 3 years

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Related Questions

Find the exact arc length of f(x)=√2x+1 0≤x≤4

Answers

The exact arc length of f(x)=√2x+1 is 4.5.

The arc length is the separation between two points along a curve segment. The arc length of a function f(x) is given by the formula,

[tex]L=\int\limits^a_b {\sqrt{1+f'(x)^2}} \, dx[/tex]

Where f'(x) is derivative of function f(x). The arc length is, to put it simply, the distance that passes across the curved line of the circle that forms the arc. It should be noted that the arc's length is greater than the separation of its ends along a straight line.

Finding the arc length of f(x)=√2x+1 0≤x≤4, using the formula,

First finding the derivative of function,

[tex]f'(x)=\frac{d(\sqrt{2x+1})}{dx} \\\\=\frac{2}{2\sqrt{2x+1}} \\\\=\frac{1}{\sqrt{2x+1}}[/tex]

Now, putting the derivative of function f(x) in the formula of arc length L,

[tex]L=\int\limits^a_b {\sqrt{1+f'(x)^2}} \, dx\\\\L=\int\limits^4_0 {\sqrt{1+(\frac{1}{\sqrt{2x+1}})^2}} \, dx\\\\L=\int\limits^4_0 {\sqrt{1+\frac{1}{2x+1}}}\\\\L=\int\limits^4_0 {\sqrt{\frac{2x+1+1}{2x+1}}}\\L=\int\limits^4_0 {\sqrt{\frac{1}{2x+1}}}\\\approx4.5[/tex]

Therefore, the exact arc length of f(x)=√2x+1 is 4.5.

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A denim shirt at a certain factory requires 2 1/5 yards of material. How many shirts can be made from 70 2/5 yards of​ material?

Answers

Answer: 32

Step-by-step explanation:

If you multiply 2 1/5 by 35 you would get 70.4, .4 is equivalent to 2/5, so 70.4 = 70 2/5.

i need the answers for the problems

Answers

Answer:

I believe the first one is log8(5/3), the second is log5(3), and the third is -2log2(5)

Step-by-step explanation:

I got this by applying the properties of logarithms which are:

logₐ mn = logₐ m + logₐ n (product property)

logₐ m/n = logₐ m - logₐ n (quotient property)

logₐ mn = n logₐ m (power property)

logb = (log꜀ a) / (log꜀ b) (change of base property)

use the distributive property to solve the equation 2x - 4(x - 2) = - 8 + 4x + 4

Answers

Is it 0 I don’t know bro

If f(x) = 2x + 1, find f(1). Just write the answer no equals or variable!!!

Answers

Answer:

3

Step-by-step explanation:

f(1)=2(1)+1

f(1)=3

The blood types of 200 people are collected at a doctor’s office. The table shows the breakdown of patients by blood type.

If a person from this group is selected at random, what is the probability that this person has type AB blood? Express your answer as a fraction in lowest terms or as a decimal rounded to the nearest millionth (if necessary).

Blood Type Survey Results
Blood Type Number of Patients
A 45
B 65
O 75
AB 15

Answers

Answer:

[tex]\frac{3}{40}=0.075[/tex]

Step-by-step explanation:

The probability of a person selected at random from this group having type AB blood is 15 out of 200 total people. Therefore:

[tex]\frac{15}{200}=\frac{3}{40}=0.075=7.5\%[/tex]

NEED HELP ASAP WILL GIVE BRAINLIEST!

3Fill blanks
1. _ 2. _<6ab+3b/3a+1<_

Answers

Answer:

Step-by-step explanation:

Line b passes through the point (4, 2) and is
perpendicular
to the x-axis. What is the slope of line b?

Answers

Answer:

The slope would be undefined

Step-by-step explanation:

If the slope is perpendicular to the x-axis that means it is vertical, all vertical lines have undefined slopes therefore the slope is undefined.

Question content area top Part 1 What is the constant of proportionality in the equation y=−7.48​x?

Answers

The constant of proportionality of the equation y =−7.48​x is - 7.48.

What is proportional relationship?

Proportional relationships are relationships between two variables where their ratios are equivalent

In other words, two variables have a proportional relationship if the ratios of the variables are equivalent.

Therefore, a proportional relationship is one in which two quantities vary directly with each other.

Hence, in mathematical form,

y ∝ x

y = kx

where

k = constant of proportionality

y varies directly as the variable x.

In the equation,

k = - 7.48

Therefore, the constant of proportionality  is - 7.48.

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In a raffle, 100 tickets are sold. George buys 10 tickets Julia by 5 tickets. There is one winning ticket. Find a probability that
a. George will win
b. jullia will win​

Answers

Probability of (a) George winning is 0.1

                       (b) Julia winning is 0.05

Given in question,

Total ticket sold = 100

George bought tickets = 10

Julia bought tickets = 5

Winning ticket = 1

Selecting 1 ticket from 100 = [tex]\left[\begin{array}{ccc}100\\1\\\end{array}\right][/tex]

                                            = 100

Selecting 1 ticket from 10 = [tex]\left[\begin{array}{ccc}10\\1\\\end{array}\right][/tex]

                                         = 10

Selecting 1 ticket from 5 = [tex]\left[\begin{array}{ccc}5\\1\\\end{array}\right][/tex]

                                        = 5

Probability = favorable outcome/total outcome

Probability of George winning = [tex]\frac{10}{100}[/tex]

                                                  = 0.1

Probability of Julia winning = [tex]\frac{5}{100}[/tex]

                                             = 0.05

Hence, probabilities are 0.1 and 0.05 respectively.

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Drag the tiles to the correct boxes to complete the pairs.
Determine whether each pair of lines is perpendicular, parallel, or neither.
2y = 4x + 4
y=-2x-2
4y= 2x - 4
y=-2x+9
Perpendicular
Parallel
y = 2x+4
2y = 4x - 7
Neither

Answers

Answer:

neitherperpendicularparallel

Step-by-step explanation:

You want to know whether the pairs of equations describe lines that are parallel, perpendicular, or neither.

Parallel

Parallel lines have the same slope. When the equations are written in slope-intercept form, the coefficients of x are identical.

Perpendicular

Perpendicular lines have opposite reciprocal slopes. When the equations are written in slope-intercept form, the product of the x-coefficients is -1.

Application1. 2y = 4x +4; y = -2x -2

Solving the first equation for y gives ...

  y = 2x +2

The x-coefficients are 2 and -2, so the lines are neither parallel nor perpendicular.

2. 4y = 2x -4; y = -2x +9

Solving the first equation for y gives ...

  y = 2/4x -1 = 1/2x -1

The x-coefficients are 1/2 and -2, which have a product of -1. These lines are perpendicular.

3. y = 2x +4; 2y = 4x -7

Solving the second equation for y gives ...

  y = 2x -7/2

The x-coefficients are 2 and 2, which are identical. These lines are parallel.

How many solutions does the equation have?
12x + 6 = 14(2x – 24) because when simplified we get?

a) 6=-6
a) infinitely many solutions
b) x=-6
b) one solution
c) 6=6
c) no solution

Answers

Answer:

One solution: x =21.6

Step-by-step explanation:

Equation

12x + 6 = 14(2x – 24)                    Remove the brackets

Solution

12x + 6 = 28x - 336                      Add 336 to both sides.

12x + 6+336 = 28x - 336             Combine

12x + 342 = 28x -336+336        

12x + 342 = 28x                            Subtract 12x from both sides.

12x-12x + 342 = 28x - 12x             Combine

342 = 16x                                      Divide by 16

342/16 = 16x/16

21.6=x  

2x+18=4x-14 pls help me - johnny

Answers

Answer: x=16

Step-by-step explanation: 18=2x-14

32=2x

x= 16

Write a coordinate rule for the composition 

Answers

Answer:

so basically u do that and then u do that and then

Step-by-step explanation:

8

A study of bone density on 5 random women at a hospital produced the following results.
Age 41, 53, 57, 61, 65.
Bone density: 360, 355, 340, 325, 310
Calculate the correlation coefficient, r. Round your answer to three decimal places.

Answers

The correlation coefficient when there is a study of bone density on 5 random women is -0.909.

What is the correlation coefficient?

It is the statistical measure of the strength of the linear relationship that's between two variables. The correlation coefficient is calculated by calculating the covariance of the variables and dividing that number by the product of the standard deviations of those variables.

The steps for calculating the correlation coefficient are as follows:

Choose your data sets.Determine the standardized value for your x variables.Determine the standardized value for your y variables.Find the sum by multiplying.Determine the correlation coefficient by dividing the total.

The statistical software was used and the values include

Dependent variable = y

Independent variable = x

It should be noted that linear regression has an equation that is in the form of Y = a + bx. The equation is y = 451.674 - 2.051. This was gotten through the statistical software used.

Sample size = 5

Correlation coefficient = -9.09

In conclusion, the coefficient is -9.09.

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Urgent .. Suppose that a national testing service gives a test in which the results are
normally distributed with a mean of 550 and standard deviation of 85. If you score a
625 on the test, what fraction of the students taking the test exceeded your score?

Answers

The fraction of the students taking the test exceeded your score will be 47 / 250.

What is a normal distribution?

The Gaussian Distribution is another name for it. The most significant continuous probability distribution is this one. Because the curve resembles a bell, it is also known as a bell curve.

Assume that a public testing administration gives a test in which the outcomes are regularly dispersed with a mean of 550 and a standard deviation of 85. On the off chance that you score a 625 on the test.

Then the fraction of the students taking the test exceeded your score will be given as,

z = (625 - 550) / 85

z = 75 / 85

z = 0.8824

Then the fraction is given as,

P(x > 625) = P(z > 0.8824)

P(x > 625) = 0.188

P(x > 625) = 47 / 250

The fraction of the students taking the test exceeded your score will be 47 / 250.

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Two mechanics worked on a car. The first mechanic charged $85 per hour, and the second mechanic charged $45 per hour. The
mechanics worked for a combined total of 15 hours, and together they charged a total of $1075. How long did each mechanic work?

Answers

The first mechanic worked for 10 hours and second mechanic worked for 5 hours.

Given,

Price of first mechanic service =$85/hr

Price of second mechanic service=$45/hr

Total time they worked together=15 hours

Total combined price charged=$1075

Let

Time spend by first mechanic on work =x

Time spend by second mechanic on work =y

Price charged by first mechanic on total work =85x

Price charged by second mechanic on total work=45y

Equation for total time spend by them together on work can be written as,

[tex]x+y=15.....i\\\\y=15-x[/tex]

Equation for total price charged by them can be written as,

[tex]85x+45y=1075\\[/tex]

Substituting y,

[tex]85x+45(15-x)=1075\\\\85x+675-45x=1075\\\\40x+675=1075\\\\40x=1075-675\\\\40x=400\\\\x=10\\[/tex]

Substituting x in eq.[tex]i[/tex],

[tex]10+y=15\\\\y=15-10\\\\y=5[/tex]

Hence, the first mechanic worked for 10 hours and second mechanic worked for 5 hours.

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Convert 2 7/12 to a percent. Round to the nearest tenth of a percent.

Answers

Answer:

2.6

Step-by-step explanation:

2 7/12

12x2=24

24+7=31

31/12=2.583333

Answer:

its 262.5%

Step-by-step explanation:

The volume V of a fixed amount of a gas varies directly as the temperature T and inversely as the pressure P. Suppose that V = 70 cm^3 when T = 420 kelvin and P = 18 kg/cm^2. Find the pressure when T = 140 kelvin and V = 60 cm^3.

Answers

The pressure of the gas is 7kg/cm^2.

How to determine the pressure of the gas?

Joint Variation is a situation in which the value of one variable depends on two, or more, other variables when the other variables are held constant

Given that: The volume V of a fixed amount of a gas varies directly as the temperature T and inversely as the pressure P. This can be written as:

VαT and Vα 1/P

Combining the two relations gives:

Thus Vα T/P  

V = kT/P        (where k is a constant)

PV=kT

k = PV/T

P =kT/V

Given: V = 70 cm^3

when T = 420 kelvin

P = 18 kg/cm^2

k = 18×70 / 420

k = 1260/420

k = 3

Given: T = 140 kelvin and

V = 60 cm^3.

Find the pressure

P = kT/V

P = 3×140/60

= 420/60

= 7kg/cm^2

Therefore, the pressure when T = 140 kelvin and V = 60 cm^3 is 7kg/cm^2.

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For all real values of x if f((x)=(x-3)^2 and g(x)=(x+3)^2 what is f(x)-g(x)?

Answers

The composition f(x) - g(x) has its value to be 12x

How to evaluate the composite function?

The definitions of the functions are given as

f(x) = (x - 3)²

Also, we have the definition of another functions to be given as

g(x) = (x + 3)²

To find the composition f(x) - g(x), we make use of the following equation

f(x) - g(x) = f(x) - g(x)

So, we have the following equation

f(x) - g(x) = f(x) - g(x)

Substitute the known values in the above equation

So, we have the following equation

f(x) - g(x) = (x + 3)² - (x - 3)²

Apply the differece of two squares rules

So, we have

f(x) - g(x) = (x + 3 + x - 3)(x + 3 - x + 3)

So, we have

f(x) - g(x) = (2x)(6)

This gives

f(x) - g(x) = 12x

Hence, the value of the composition is f(x) - g(x) = 12x

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I know this is easy for some, but I have no idea what happened here. Can someone explain to me? These are congruent triangles.

8x -13 = 5x + 17
3x = 30
x = 10​

Answers

The x value we get is 10 when the sides are 8x-13 and 5x+17 in a congruent triangle.

Given that,

The sides as 8x-13 and 5x+17

We have to find the x value.

If two or more triangles are congruent, it depends on how big their sides and angles are. The three sides and three angles of a triangle determine its size and shape, accordingly. Two triangles are said to be congruent if the pairings of respective sides and corresponding angles are equal.

We say now,

8x-13 = 5x+17

8x-5x=17+13

3x=30

x=30/3

x=10

Therefore, The x value we get is 10 when the sides are 8x-13 and 5x+17 in a congruent triangle.

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a.) find the test statistic
b.) what is the p-value
c.)what is the conclusion about the null hypothesis
d.) what is the final conclusion?

Answers

Regarding the hypothesis tested in this problem, it is found that:

a) The test statistic is: t = 0.49.

b) The p-value is: 0.6297..

c) The null hypothesis is not rejected, as the p-value is greater than the significance level.

d) It appears that the students are legitimately good at estimating one minute, as the sample does not give enough evidence to reject the null hypothesis.

What is the test statistic?

The test statistic of the t-distribution is given by the equation presented as follows:

[tex]t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}[/tex]

In which the variables of the equation are given as follows:

[tex]\overline{x}[/tex] is the sample mean.[tex]\mu[/tex] is the value tested at the hypotheses.s is the standard deviation of the sample.n is the sample size.

The value tested at the hypothesis is:

[tex]\mu = 60[/tex]

From the sample, using a calculator, the other parameters are given as follows:

[tex]\overline{x} = 62.47, s = 19.2, n = 15[/tex]

Hence the test statistic is obtained as follows:

[tex]t = \frac{\overline{x} - \mu}{\frac{s}{\sqrt{n}}}[/tex]

[tex]t = \frac{62.47 - 60}{\frac{19.2}{\sqrt{15}}}[/tex]

t = 0.49.

What are the p-value and the conclusion?

The p-value is obtained using a t-distribution calculator, with a two-tailed test, as we are testing if the mean is different a value, in this case 60, with:

15 - 1 = 14 df, as the number of degrees of freedom is one less than the sample size.t = 0.49, as obtained above.

Hence the p-value is of 0.6297.

Since the p-value is greater than the significance level of 0.01, the null hypothesis is not rejected, attesting to the ability of the students to estimate one minute.

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2x + 4y = 4


number of solution

Answers

Given equation 2x + 4y = 4 has infinitely many solutions.

We have been given an equation 2x + 4y = 4

We need to find the number of solutions.

Above equation is a linear equation with two variables.

We know that, a linear equation in two variables has infinitely many solutions.

For any value real value of x we can find corresponding value of y.

Since x can takes infinitely many inputs the output would be infinitely many.

Therefore, given equation 2x + 4y = 4 has infinitely many solutions.

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the graph of f(x)=x^3+3x^2-4 is shown. what is the value of f^-1(-4)

Answers

Since the function is not one-to-one, the inverse function of f(x) = x³ + 3x² - 4 is not defined at x = -4.

How to obtain the numeric value of the inverse function?

An original function is composed by a set of points in the following format:

(x,y).

On the graph of the function, we have that:

The x-coordinate represents the input of the function, being the horizontal axis of the graph.The y-coordinate represents the output of the function, being the vertical axis of the graph.

On the inverse function, the input and the output are exchanged, hence the format of the point is:

(y,x).

To find the numeric value of the inverse function at x = -4, we need to identify the value of x on the original function where y = -4.

However, looking at the graph of the function given at the end of the answer, the function is not one-to-one at y = -4, since f(-3) = f(0) = 4, thus the inverse function is not defined at x = -4.

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What 1+2

Apparently that wasn’t enough info…

Answers

Answer:

3???

Step-by-step explanation:

which of the following is a polynomial 5x^2+3

Answers

The correct option regarding which option represents a polynomial is given as follows:

b. ii only.

What are polynomials?

Polynomials are expressions that are given in the following format:

[tex]p(x) = a_nx^n + a_{n-1}x^{n - 1} + \cdots + a_1x + a_0[/tex]

In which n is the degree of the polynomial.

The exponents n have to be all whole numbers for the expression to represent a polynomial, meaning that they cannot be negative neither fractions or decimal values.

Thus the only expression that represents a polynomial is:

ii. 5x³ + 3x² + x + 2.

The reasons for the expressions that do not represent a polynomial are given as follows:

Expression i: Negative exponents.Exponent iii: Fractional exponents, due to the root.

Hence the correct option is given by option b.

Missing Information

The problem is given by the image at the end of the answer.

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Craig mows two lawns. The first lawn is 40 meters long and 20 meters wide. The second lawn has the same length, and a width that is 4 times as much as the first one. What is the total area of the two lawns??​

Answers

The area of two lawns will be 4000 square meters.

According to the question,

We have the following information:

Craig mows two lawns. The first lawn is 40 meters long and 20 meters wide. The second lawn has the same length, and a width that is 4 times as much as the first one.

So, the width of the second lawn = 4*20

Width of second lawn = 80 m

Now, formula to find area of rectangle:

Length*width

Area of first lawn:

40*20

800 square meters

Area of second lawn:

40*80

3200 square meters

Now, the area of two lawns = area of first lawn+ area of second lawn

Area = 800+3200

Area = 4000 square meters

Hence, the total area of two lawns is 4000 square meters.

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Please Help 25 points

Answers

R and 35.9 are vertical angles, so they are congruent

R = 35.9º

What is 804082 written in expanded form

Answers

Answer:

Step-by-step explanation:

(8 x 100000) + (0 x 10000) + (4 x 1000) + (0 x 100) + (8 x 10) + (2 x 1) = 804082

Josh loves to visit his aunt's house. When there, his two favorite activities are walking the dog and playing darts. Let A represent the event that he walks his dog at his aunt's house and B represent the event that he plays darts at his aunt's house. If A and B are independent events with P(A)=0.9 and P(B)=0.4, find P(A AND B).

Answers

The probability of P(A AND B) when Josh visit his aunt's house is 0.36.

What is probability?

Probability is the likelihood that an event will occur or take place.

Let A = the event that he walks his dog at his aunt's house

Let B = the event that he plays darts at his aunt's house.

When A and B are independent events with P(A)=0.9 and P(B)=0.4, the probability of P(A AND B) will be:

= P(A) × P(B)

= 0.9 × 0.4

= 0.36

The probability is 0.36.

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