Assuming the below results were obtained in a study used to test the accuracy of the rapid diagnostic test for influenza, calculate and interpret the sensitivity of the rapid diagnostic influenza test.
Frequency of Flu Cases Frequency of Non-Fu Cases
Frequency of Individuals who 47 10
Screened Positive
Frequency of individuals who 43 100
Screened Negative
A) When the rapid diagnostic influenza test is used, 52.22% of individuals who have the flu test positive for the flu.
B) When the rapid diagnostic influenza test is used, 90.91% of individuals who have the flu test positive for the
C) When the rapid diagnostic influenza test is used, 47.78% of individuals who have the flu test positive for the flu.
D) When the rapid diagnostic influenza test is used, 9.09% of individuals who have the flu test positive for the flu.

Answer:

x>−6 and x<7

Step-by-step explanation:

Let's solve your inequality step-by-step.

|−2x+1|<13

Solve Absolute Value.

|−2x+1|<13

We know−2x+1<13and−2x+1>−13

−2x+1<13(Condition 1)

−2x+1−1<13−1(Subtract 1 from both sides)

−2x<12

−2x

−2

<

12

−2

(Divide both sides by -2)

x>−6

−2x+1>−13(Condition 2)

−2x+1−1>−13−1(Subtract 1 from both sides)

−2x>−14

−2x

−2

>

−14

−2

(Divide both sides by -2)

x<7

Answer:

x>−6 and x<7

Answer:

2835

Step-by-step explanation:

(21×15)9=

(315)9=

2835

Answer:

Step-by-step explanation:

a) Number of variables in the data set : 5

b) A quantitative variable is the one which can be quantitatively measured. i.e. it is a numerical value.

A categorical variable is the one that can take one value from a limited number of fixed values.

Exchange is a Categorical Variable. Price/Earnings Ratio is a Quantitative Variable. Gross Profit Margin (%) is a Quantitative Variable.

c. Out of the 25 stocks, AMEX is the exchange for 5 stocks. So percent frequency is 5/25 = 0.2 = 20%.

NYSE is the exchange for 3 stocks. So percent frequency is 3/25 = 0.12 = 12%.

OTC is the exchange for 17 stocks. So percent frequency is 17/25 = 0.68 = 68%.

These percentages are correctly shown in graph a. So the answer is a.

d) The frequency distribution is

Gross Profit Margin                Frequency

0-14.9                                        2

15-29.9                                      6

30-44.9                                     8

45.59.9                                    6

60.74.9                                    3

As we come across the Gross Profit Margin values in the table, we add a | next to its respective interval and build the above table. E.g. the first value in the table under Gross Profit Margin is 36.7 which lies in the interval 30–44.9. So we add one | in fromt of that interval and so on until we cover the entire table. The number of | shows the frequency distribution of the values.

The correct histogram is A.

e. The average price/earnings ratio is found by adding all the 25 values in the table and dividing the answer by 25.

= 505.40/25

Answer:

[tex]\fbox{\begin{minipage}{5em}A = 18.3\end{minipage}}[/tex]

Step-by-step explanation:

Given:

Dan was thinking of a number.

Dan adds 10 to it, then doubles it and gets an answer of 56.6.

Solve for:

Dan's original number

Step 1: Clarify the problem:

Denote Dan's original number as A

Dan adds 10 to A => 10 + A, then

Dan doubles this sum => 2 x (10 + A), then

Dan gets an answer of 56.6 => 2 x (10 + A) = 56.6

Step 2: Solve for the defined equation:

2 x (10 + A) = 56.6

Let's divide both sides of equation by 2:

2 x (10 + A)/2 = 56.6/2

We simplify both sides after division:

10 + A = 28.3

Let's transfer all numbers to the right side, except A (the sign of 10 is changed from + to -)

A = 28.3 - 10

Let's perform the subtraction to get A:

A = 18.3

Hope this helps!

:)

Answer:

D.

Step-by-step explanation:

It's a right triangle so

[tex]x^2=40^2+9^2[/tex]

x = 41

Step-by-step explanation:

work is shown and pictured

The discriminant of quadratic equation is,

⇒ D = 0

What is Quadratic equation?

The definition of a quadratic as a second-degree polynomial equation demands that at least one squared term must be included. It also goes by the name quadratic equations. The quadratic equation has the following generic form:  ax² + bx + c = 0

We have to given that;

Quadratic equation is,

⇒ - 3 = x² + 4x + 1

Now, We can write as;

⇒ x² + 4x + 1 + 3 = 0

⇒ x² + 4x + 4 = 0

Hence, Discriminant of quadratic equation is,

⇒ D = b² - 4ac

⇒ D = (4)² - 4×1×4

⇒ D = 16 - 16

⇒ D = 0

Thus, The discriminant of quadratic equation is,

⇒ D = 0

Learn more about the quadratic equation visit:

brainly.com/question/1214333

#SPJ7

Answer:

x: -5,  -3,   0,  1,  4

y:-23, -15, -3, 1, 13        for the function.

x:-23, -15, -3, 1, 13

y: -5,   -3,  0,  1,  4         for the inverse.

Step-by-step explanation:

we know that if we have the function f(x) = y, then the inverse of f(x) (let's call it g(x)) is such that:

g(y) = x.

now we have

y=4x-3

y=(1/4)x+3/4

The only table that works for our first function is:

x: -5,  -3,   0,  1,  4

y:-23, -15, -3, 1, 13

You can see this by replacing the values of x and see if the value of y also coincides.

Then, using the fact that the other table must be for the inverse, we should se a table with the same values, but where the values of x and y are interchanged.

The second table is that one:

x:-23, -15, -3, 1, 13

y: -5,   -3,  0,  1,  4

Answer: B and D

x:-23, -15, -3, 1, 13

y:-5, -3, 0, 1, 4

x:-5, -3, 0, 1, 4

y:-23, -15, -3, 1, 13

Step-by-step explanation:

answer: D) 439.85

Step-by-step explanation:

we are given the price of the bike which is $413.

we are also given the sales tax which is 6.5%.

sales tax is added to the original price to give us our total. so in order to find the total cost we need to find what the 6.5% sales tax is and add it to our original price. to find the sales tax number in dollars we need to set up our formula. The easiest formula is to use a proportion. X is out of 413 = 6.5% is out of 100%. X/413=6.5/100. We can then cross multiply then divide. 6.5 times 413=2,684.5. then divide 2684.5÷100= 26.845.

we need to round up to the nearest cent since we are working with dollars and cents 26.85. 26.85 is 6.5% of the price of the bike which is 413. Now we just simply add the tax to the original price and we get the cost. 413+26.85=439.85

Answer:    The answer is D) 439.85

Step-by-step explanation:

Step-by-step explanation:

1039

This is the correct answer

The probability that it also rained that day would be 0.30

Answer:

160 units and $6400

Step-by-step explanation:

We have that the cost per x unit is: 20 * x + 0.25 * x ^ 2

the price per unit is 100, therefore revenue for each unit would be 100 * x

However:

profit = revenue - cost

p (x) = 100 * x - 20 * x - 0.25 * x ^ 2

for the maximum value profit we must derive and equal 0:

p '(x) = 100 - 20 - 0.5 * x

0 = 80 - 0.5 * x

0.5 * x = 80

x = 80 / 0.5

x = 160

Therefore, the maximum profit occurs when there are 160 units, replacing we have:

p (x) = 100 * 160 - 20 * 160 - 0.25 * 160 ^ 2

p (x) = 6400

that is to say that the $ 6400 is the maximum profit.

Answer:

The mean of depth is 12.75cm.

The variance of depth is of 13.02 cm².

Step-by-step explanation:

An uniform probability is a case of probability in which each outcome is equally as likely.

For this situation, we have a lower limit of the distribution that we call a and an upper limit that we call b.

The mean of the uniform distribution is:

[tex]M = \frac{a+b}{2}[/tex]

The variance of the uniform distribution is given by:

[tex]V = \frac{(b-a)^{2}}{12}[/tex]

Uniform distribution on the interval (6.5, 19)

This means that: [tex]a = 6.5, b = 19[/tex]

So

Mean:

[tex]M = \frac{6.5+19}{2} = 12.75[/tex]

The mean of depth is 12.75cm.

Variance:

[tex]V = \frac{(19 - 6.5)^{2}}{12} = 13.02[/tex]

The variance of depth is of 13.02 cm².

Answer:

Please show the graph choice it sounds linear xy (positive)

or parallel depending on how much pens and pencils were.

We know $18 purchased more than 1 pack so this divided by notebook shws us at least 6 per notepack paper or so many packs of pen that cost $18 ffor pens were ratio to 1 pack of paper. ie) if pens were £2 pack then while we understand it could have been as many as 9 we divide by how many we find or bought by the amount of notepaper books to determine the rate and distribution of the money.    

Step-by-step explanation:

$39 - $18 = $21 left over

21/3 = 7 packs of note paper can be purchased..

Step-by-step explanation:

You can take the inverse of a function by replacing all x-values in the equation with y-values and vice versa and subsequently solving for y:

Equation given:

[tex]f(x) = \frac{-x}{x+2}[/tex]

Replace all x-values with y and all y-values with x:

[tex]x = \frac{-y}{y+2}[/tex]

Solve for y:

[tex]x(y+2) = -y\\\\xy + 2x = -y\\\\2x = -y - xy\\\\2x = y(-1+-x)\\\\-\frac{2x}{x+1} =y[/tex]

This is the inverse of f(x), where x ≠ 2..

Answer:

( 5 ^ -2)^4

= 5 ^ -8

= 1 /5^8

= 1 / 390,625

Answer:

a. In the explanation.

b. The point estimate of the difference can be calculated as the difference between the sample mean and the population mean:

[tex]d=M-\mu=24.95-23.8=1.15[/tex]

c. Test statistic t = 0.90

P-value = 0.1932

The null hypothesis failed to be rejected.

Step-by-step explanation:

We have a sample, wich mean and standard deviation are calculated as:

[tex]M=\dfrac{1}{14}\sum_{i=1}^{14}(27.8+23.84+25.25+21+17.52+19.61+...+26.94+27.24)\\\\\\ M=\dfrac{349.34}{14}=24.95[/tex]

[tex]s=\sqrt{\dfrac{1}{(n-1)}\sum_{i=1}^{14}(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{13}\cdot [(27.8-(24.95))^2+(23.84-(24.95))^2+...+(27.24-(24.95))^2]}\\\\\\s=\sqrt{\dfrac{1}{13}\cdot [(8.106)+(1.238)+...+(5.23)]}\\\\\\ s=\sqrt{\dfrac{304.036}{13}}=\sqrt{23.39}\\\\\\s=4.8[/tex]

This is a hypothesis test for the population mean.

The claim is that the consumption of milk in the Midwest is significantly higher than the national average.

Then, the null and alternative hypothesis are:

[tex]H_0: \mu=23.8\\\\H_a:\mu> 23.8[/tex]

The significance level is 0.01.

The sample has a size n=14.

The sample mean is M=24.95.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=4.8.

The estimated standard error of the mean is computed using the formula:

[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{4.8}{\sqrt{14}}=1.28[/tex]

Then, we can calculate the t-statistic as:

[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{24.95-23.8}{1.28}=\dfrac{1.15}{1.28}=0.9[/tex]

The degrees of freedom for this sample size are:

[tex]df=n-1=14-1=13[/tex]

This test is a right-tailed test, with 13 degrees of freedom and t=0.9, so the P-value for this test is calculated as (using a t-table):

[tex]\text{P-value}=P(t>0.9)=0.1932[/tex]

As the P-value (0.1932) is bigger than the significance level (0.01), the effect is not significant.

The null hypothesis failed to be rejected.

There is not enough evidence to support the claim that the consumption of milk in the Midwest is significantly higher than the national average.

Answer:

24π

Step-by-step explanation:

If the diameter is 4, the radius is 2

V = [tex]\pi r^2 *h[/tex]

r = 2

h = 6

24π

Answer:

Step-by-step explanation:

diameter: 4 inch (Radius is 2)

V

If the diameter is 4, the radius is 2

V is  r^2*h

the radius is 6

so it’s 24

Answer:

[tex](\frac{3}{8}\,in )^2=\frac{9}{64} \,in^2=0.140625\,\,i^2[/tex]

Step-by-step explanation:

Recall that the formula for the area of a square of side L is: [tex]Area=L^2[/tex]

Therefore, for this case:

[tex]Area=L^2\\Area = (\frac{3}{8} \,in)^2\\Area=\frac{9}{64} \,\,in^2\\Area=0.140625\,\,in^2[/tex]

Due to the symmetry of the paraboloid about the z-axis, you can treat this is a surface of revolution. Consider the curve [tex]y=x^2[/tex], with [tex]1\le x\le2[/tex], and revolve it about the y-axis. The area of the resulting surface is then

[tex]\displaystyle2\pi\int_1^2x\sqrt{1+(y')^2}\,\mathrm dx=2\pi\int_1^2x\sqrt{1+4x^2}\,\mathrm dx=\frac{(17^{3/2}-5^{3/2})\pi}6[/tex]

But perhaps you'd like the surface integral treatment. Parameterize the surface by

[tex]\vec s(u,v)=u\cos v\,\vec\imath+u\sin v\,\vec\jmath+u^2\,\vec k[/tex]

with [tex]1\le u\le2[/tex] and [tex]0\le v\le2\pi[/tex], where the third component follows from

[tex]z=x^2+y^2=(u\cos v)^2+(u\sin v)^2=u^2[/tex]

Take the normal vector to the surface to be

[tex]\dfrac{\partial\vec s}{\partial u}\times\dfrac{\partial\vec s}{\partial u}=-2u^2\cos v\,\vec\imath-2u^2\sin v\,\vec\jmath+u\,\vec k[/tex]

The precise order of the partial derivatives doesn't matter, because we're ultimately interested in the magnitude of the cross product:

[tex]\left\|\dfrac{\partial\vec s}{\partial u}\times\dfrac{\partial\vec s}{\partial v}\right\|=u\sqrt{1+4u^2}[/tex]

Then the area of the surface is

[tex]\displaystyle\int_0^{2\pi}\int_1^2\left\|\dfrac{\partial\vec s}{\partial u}\times\dfrac{\partial\vec s}{\partial v}\right\|\,\mathrm du\,\mathrm dv=\int_0^{2\pi}\int_1^2u\sqrt{1+4u^2}\,\mathrm du\,\mathrm dv[/tex]

which reduces to the integral used in the surface-of-revolution setup.

Answer:

a) The 95% confidence interval for the mean amount of time Americans age 15 or older spend eating and drinking each day is (1.49, 1.57).

d) The nutritionist is 95% confident that the mean amount of time spent eating or drinking per day for any individual is between 1.49 and 1.57 hours.

(c and b can not be concluded from the confidence interval)

Step-by-step explanation:

We have to calculate a 95% confidence interval for the mean.

The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.

The sample mean is M=1.53.

The sample size is N=1082.

When σ is not known, s divided by the square root of N is used as an estimate of σM:

[tex]s_M=\dfrac{s}{\sqrt{N}}=\dfrac{0.71}{\sqrt{1082}}=\dfrac{0.71}{32.89}=0.022[/tex]

The degrees of freedom for this sample size are:

[tex]df=n-1=1082-1=1081[/tex]

The t-value for a 95% confidence interval and 1081 degrees of freedom is t=1.962.

The margin of error (MOE) can be calculated as:

[tex]MOE=t\cdot s_M=1.962 \cdot 0.022=0.042[/tex]

Then, the lower and upper bounds of the confidence interval are:

[tex]LL=M-t \cdot s_M = 1.53-0.042=1.49\\\\UL=M+t \cdot s_M = 1.53+0.042=1.57[/tex][tex]LL=M-t \cdot s_M = 1.53-0.042=1.49\\\\UL=M+t \cdot s_M = 1.53+0.042=1.57[/tex]

The 95% confidence interval for the mean is (1.49, 1.57).

Answer:

The equations are linearly independent so there is no parametric vector form

Step-by-step explanation:

I attached the solution.

Answer:

Step-by-step explanation:

1) d

2) c

1) 3 hearts, 7 other shapes that isn't hearts

2) 2 triangs, 5 circles

Answer:

1) d

2) c

Step-by-step explanation:

looks like i was wrong last time lol, this is right for sure tho, i see what i did wrong, sorry

Answer:

Step-by-step explanation:

No Solutions

There will be no solutions when the left side is inconsistent with the right side:

  2x +5 +2x +3x = 7x +1

  7x +5 = 7x +1 . . . . . . no value of x will make this true

__

One Solution

There will be one solution when the left side and right side are not inconsistent and not the same.

  2x +5 +2x +3x = 6x +1

  7x +5 = 6x +1

  x = -4 . . . . . . . . add -6x-5 to both sides

__

Infinitely Many Solutions

There will be an infinite number of solutions when the equation is true for any value of x. This will be the case when the left side and right side are identical.

  2x +5 +2x +3x = 7x +5

  7x +5 = 7x +5 . . . . . true for all values of x

_____

Comment on these solutions

You have not provided the contents of any of the drop-down menus, so we cannot say for certain what the answers should be--except in the case of "infinitely many solutions." For "no solutions", the coefficient of x must be 7 and the constant must not be 5. For "one solution" the coefficient of x cannot be 7, and the constant can be anything.

Answer:

No Solutions: 7x+1

One Solution: 6x+1

Infinitely Many Solutions: 7x+5

Answer:

A

Step-by-step explanation:

We can see that Function A's y coordinate doubles every time. The function A = f(x) = 5(2)^x. It is an exponential growth function, and therefore y can never be 0. This means that A does not have an x-intercept.

Function B is a rational function. x cannot be 0, since that would result in an undefined number. This also means that B does not have an x-intercept.

Answer:D

Step-by-step explanation:

-2=4/5(0)-2

-2=0-2

-2=-2

-6/5=4/5(1)-2

-6/5=4/5-10/5

-6/5=4/5-10/5

-6/5=-6/5

Answer:

A . 0.85 + (0.15 +(-3)) = -2

B . [(-3)+(-3)]+(-3) = - 9

Step-by-step explanation:

Explanation:-

Associative  property with addition

(a+(b+c)) = (a+b) + c

A)

Given 0.85 + (0.15 +(-3)) = (0.85 +0.15)+(-3)

                                       = 1 - 3

                                       = -2

B)  Given [(-3)+(-3)]+(-3) = ( (-3)+[( -3)+(-3))]

                                     = ( -3 +[-3-3]

                                    =  -3 -6

                                    = -9

Final answer:-

A . 0.85 + (0.15 +(-3)) = -2

B . [(-3)+(-3)]+(-3) = - 9

Answer:

"According to the 68-95-99.7 rule, we expect 95% [95.45%] of head breadths to be" between 4.1 inches and 8.9 inches.

Step-by-step explanation:

According to the 68-95-99.7 rule, approximately:

Then, if we have--from the question--that:

We have to remember that two parameters characterize a normal distribution: the population's mean and the population's standard deviation. So, mathematically, the distribution we have from question is [tex] \\ N(6.5, 1.2)[/tex].

For 95% (95.45%) of the head breadths, we expect that they are two standard deviations below and above the population's mean.

For solving this, we need to use the cumulative standard normal distribution (in case we need to find probabilities) and also use standardized values or z-scores:

[tex] \\ z = \frac{x - \mu}{\sigma}[/tex] [1]

A z-score "tells us" the distance from the mean in standard deviations units. If the z-score is positive, it is above the mean. If it is negative, it is below the mean.

Since 95% (95.45%) of the head breadths are two standard deviations (above and below the mean), we have (using [1]):

[tex] \\ \pm2 = \frac{x - \mu}{\sigma}[/tex]

But we already know that [tex] \\ \mu=6.5[/tex] inches and [tex] \\ \sigma=1.2[/tex] inches.

Thus (without using units) for values above the population's mean:

[tex] \\ 2 = \frac{x - 6.5}{1.2}[/tex]

Solving the equation for x, we multiply by 1.2 at each side of [1] :

[tex] \\ 2 * 1.2 = \frac{x - 6.5}{1.2} * 1.2[/tex]

[tex] \\ 2 * 1.2 = (x - 6.5)\frac{1.2}{1.2}[/tex]

[tex] \\ 2 * 1.2 = (x - 6.5)\frac{1.2}{1.2}[/tex]

[tex] \\ 2 * 1.2 = (x - 6.5)*1[/tex]

[tex] \\ 2 * 1.2 = x - 6.5[/tex]

Adding 6.5 at each side of the previous equation:

[tex] \\ (2 * 1.2) + 6.5 = x - 6.5 + 6.5[/tex]

[tex] \\ (2 * 1.2) + 6.5 = x + 0[/tex]

[tex] \\ (2 * 1.2) + 6.5 = x[/tex]

Therefore, the raw value, x, in the distribution that is two standard deviations above the population's mean is:

[tex] \\ x = (2 * 1.2) + 6.5[/tex]

[tex] \\ x = 2.4 + 6.5[/tex]

[tex] \\ x = 8.9[/tex] inches.

For two standard deviations below the mean, we proceed in the same way:

[tex] \\ -2 = \frac{x - 6.5}{1.2}[/tex]

[tex] \\ -2*1.2 = x - 6.5[/tex]

[tex] \\ (-2*1.2) + 6.5 = x[/tex]

[tex] \\ x = (-2*1.2) + 6.5[/tex]

[tex] \\ x = -2.4 + 6.5[/tex]

[tex] \\ x = 4.1[/tex] inches

Therefore, "according to the 68-95-99.7 rule, we expect 95% [95.45%] of head breadths to be" between 4.1 inches and 8.9 inches.

The graph below shows these values, and the shaded area represents 95% of the data, or, to be more precise, 95.45% (0.954499).  

Answer:

[tex]=3\frac{5}{6}[/tex]

Step-by-step explanation:

[tex]2\frac{1}{2}+1\frac{1}{3}\\\mathrm{Add\:whole\:numbers}\:2+1:\quad 3\\\mathrm{Combine\:fractions}\:\frac{1}{2}+\frac{1}{3}:\quad \frac{5}{6}\\=3\frac{5}{6}[/tex]

Answer:

51.56% probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question, we have that:

[tex]\mu = 3181, \sigma = 119, n = 49, s = \frac{119}{\sqrt{49}} = 17[/tex]

What is the probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd

Lower than 3181 - 11 = 3170 lbs or greater than 3181 + 11 = 3192 lbs. Since the normal distribution is symmetric, these probabilities are equal. So i will find one of them, and multiply by 2.

Probability of mean weight lower than 3170 lbs:

This is 1 subtracted by the pvalue of Z when X = 3170. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{3170 - 3181}{17}[/tex]

[tex]Z = -0.65[/tex]

[tex]Z = -0.65[/tex] has a pvalue of 0.2578

2*0.2578 = 0.5156

51.56% probability that the mean weight of the sample of cows would differ from the population mean by greater than 11lbs if 49 cows are sampled at random from the herd

Answer:

18, 13

Step-by-step explanation:

x=4+1/2y

x+y=31

4+1/y+y=31

3/2y=27

y=18

x=31-18=13

Answer:

13 & 18

Step-by-step explanation:

Create the formulas:

0.5x+4=y

x+y=31

0.5x+4=y

Multiply both sides by 2

x+8=2y

x+y=31

Subtract 31 from both sides

x+y-31=0

Subtract y from both sides

x-31= -y

Multiply both sides by -1

-x+31=y

Multiply both sides by 2

-2x+62=2y

Combine equations:

-2x+62=x+8

Add 2x to both sides

62=3x+8

Subtract 8 from both sides

3x=54

Divide both sides by 3

x=18

0.5x+4=y

Subtract y from both sides

0.5x-y+4=0

Subtract 0.5x from both sides

-y+4= -0.5x

Multiply both sides by -1

y-4=0.5x

Multiply both sides by 2

2y-8=x

x+y=31

Subtract y from both sides

x= -y+31

Combine equations:

2y-8= -y+31

Add y to both sides

3y-8=31

Add 8 to both sides

3y=39

Divide both sides by 3

y=13