The sum of two numbers is 28. The first number, x, is three times the second number, y.

Which system of equations can be used to find the two numbers?

A system of equations. x plus y equals 28. x equals 3 plus y.
A system of equations. x y equals 28. x equals 3 y.
A system of equations. x y equals 28. x equals 3 plus y.
A system of equations. x plus y equals 28. x equals 3 y.

Answers

Answer 1

Answer: x plus y equals 28. x equals 3 y.

Step-by-step explanation:

The equation can be written as

x+y=28

x=3y

x is already partially solved here, so you could substitute it into the first equation to solve for y.

3y+y=28

4y=28

y=7  We have y, so substitute that in the second equation to solve for x.

x=3(7)

x=21

We now know that x=21 and y=7

Substitute the values into the first equation:

21+7=28

28=28

So that system of equations is correct.

Answer 2

Answer:

i think its d

Step-by-step explanation:


Related Questions

Write the piecewise defined function for the total cost of parking in the garage. That is, state the function C(x), where x is the number of hours a car is parked in the garage.

Answers

Answer:

[tex]C(x) = \left[\begin{array}{ccc}4x &0 \le x \le 2& \\4 +2x &2 < x \le 6& \\16 &6<x\le 8& \end{array}\right[/tex]

Step-by-step explanation:

Given

See attachment for question

Required

The piece-wise function

From the attachment, we have:

(1) $4/hr for first 2 hours

This is represented as:

[tex]C(x) = 4x[/tex]

The domain is: [tex]0 \le x \le 2[/tex]

(2) $2/hr for next 4 hours

Here, we have:

[tex]Rate = 2[/tex]

The total cost in the first 2 hours is:

[tex]C(x) = 4x[/tex]

[tex]C(2) = 4*2 = 8[/tex]

So, this function is represented as:

[tex]C(x) = C(2) + Rate * (Time - 2)[/tex] ----- 2 represents the first 2 hours

So, we have:

[tex]C(x) = C(2) + Rate * (Time - 2)[/tex]

[tex]C(x) =8 + 2(x - 2)[/tex]

Open brackets

[tex]C(x) =8 + 2x - 4[/tex]

Collect like terms

[tex]C(x) =8 - 4+ 2x[/tex]

[tex]C(x) =4+ 2x[/tex]

The domain is:

[tex]2 < x \le 2 + 4[/tex]

[tex]2 <x \le 6[/tex]

(3) 0 charges for the last 2 hours

The maximum charge from (2) is:

[tex]C(x) =4+ 2x[/tex]

[tex]C(6) = 4 + 2*6[/tex]

[tex]C(6) = 4 + 12[/tex]

[tex]C(6) = 16[/tex]

Since there will be no additional charges, then:

[tex]C(x) = 16[/tex]

And the domain is:

[tex]6 < x \le 8[/tex] --- 8 represents the limit

So, we have:

[tex]C(x) = \left[\begin{array}{ccc}4x &0 \le x \le 2& \\4 +2x &2 < x \le 6& \\16 &6<x\le 8& \end{array}\right[/tex]

A Basketball team won 8 games and lost 7 games. What are the odds in favor of winning a basketball game

Answers

Answer:

0.47

Step-step explanation:

Add 8+7 which gives you 15. So 7/15. Then turn it into decimal form which is 0.47. Hope this helps!

0.47


Explanation:
That would be your answer

Please solve the problem

Answers

Answer:

does this have to do with graphs

Given the data, identity the type of data for each variable. (For example, determine whether the variable Day is categorical or quantitative data). Which variable is most appropriate to summarize using ungrouped frequency distributions

Answers

Answer:

Kindly check explanation

Step-by-step explanation:

The variables in the heavenly chocolate dataset is attached below :

Variables are classed as either Categorical or Quantitative.

Categorical variables are used for non - numeric variables which are used to group values based on labels whole quantitative variables are those which are numeric.

Therefore, the variables ;

Customer = Quantitative (represented with number values)

Day = Categorical (Non-numeric)

Browser = Categorical (Non - numeric)

Time = Quantitative (contains numeric values)

Pages viewed = Quantitative (contains numeric values)

Amount spent = Quantitative (contains numeric values)

Quantitative variables are most appropriate to summarize using ungrouped frequency as the attributed of the data can be adequately ibtia Ed without have to seperates or place data into categories.

5
13


The probabilities that three men win their respective races are 1/3,3/5and 3/4.what is theprobability that
a) all of them win their races)
b) only one of them win his race?

Answers

Answer:

a

Step-by-step explanation:

1/3 x 3/5 x 3/4 =7/12 so therefore that's what the answer isn't

A baseball team plays in a stadium that holds 58000 spectators. With the ticket price at $12 the average attendance has been 25000. When the price dropped to $9, the average attendance rose to 29000. Assume that attendance is linearly related to ticket price.

Required:
a. Find the demand function p(x), where x is the number of the spectators.
b. How should ticket prices be set to maximize revenue?

Answers

Answer:

We need to assume that the relationship is linear.

a) Remember that a linear relation is written as:

y = a*x + b

then we will have:

p(x) = a*x + b

where a is the slope and b is the y-intercept.

If we know that the line passes through the points (a, b) and (c, d), then the slope can be written as:

y = (d - b)/(c - a)

In this case, we know that:

if the ticket has a price of $12, the average attendance is 25,000

Then we can define this with the point:

(25,000 , $12)

We also know that when the price is $9, the attendance is 29,000

This can be represented with the point:

(29,000, $9)

Then we can find the slope as:

a = ($9 - $12)/(29,000 - 25,000) = -$3/4,000 = -$0.00075

Then the equation is something like:

y = (-$0.00075)*x + b

to find the value of b we can use one of the known points.

For example, the point (25,000 , $12) means that when x = 25,000, the price is $12

then:

$12 = (-$0.00075)*25,000 + b

$12 = -$18.75 + b

$12 + $18.75 = b

$30.75 = b

Then the equation is:

p(x) = (-$0.00075)*x + $30.75

b) We want to find the ticket price such that it maximizes the revenue.

The revenue will be equal to the price per ticket, p(x) times the total attendance, x.

Then the revenue can be written as:

r(x) = x*p(x) = x*( (-$0.00075)*x + $30.75 )

r(x) =  (-$0.00075)*x^2 + $30.75*x

So we want to find the maximum revenue.

Notice that this is a quadratic equation with a negative leading coefficient, thus the maximum will be at the vertex.

Remember that for an equation like:

y = a*x^2 + bx + c

the x-value of the vertex is:

x = -b/2a

Then in our case, the x-value will be:

x = -$30.75/(2*(-$0.00075)) = 20,500

Then the revenue is maximized for x = 20,500

And the price for this x-vale is given by:

p( 20,500) =  (-$0.00075)*20,500 + $30.75 = $15.375

which should be rounded to $15.38

A researcher utilizes a t-test to compare the average amount of beta-lactamase produced by two different types of bacteria. The Levene's test for equality of variances has a p value of 0.01. You know this means:

Answers

Answer:

The answer is "T-test results must not be presented if the same variations are expected".

Step-by-step explanation:

A t-test is used by a scientist to compare the average beta-lactamase of two distinct strains of bacteria. The Levene equality test does have a p-value of 0.01. Researchers know that all this means that research should report t-test findings with a failed assumption of identical variances because the Log-rank equality test has a p-value of 0.01 of less than 0.05 that shows different twp population variance.

solve for x : 2(x^2+9)-4=0

Answers

Answer:

no solution

Step-by-step explanation:

multiply 2 and get 2x^2+18-4=0

combine like terms

2x^2+14=0

subtract 14

2x^2=-14

there can't be a square root of a negative number so there's no solution

Answer:

x = ±i sqrt(7)

Step-by-step explanation:

2(x^2+9)-4=0

Add 4 to each side

2(x^2+9)-4+4=0+4

2(x^2+9)=4

Divide by 2

2(x^2+9)/2=4/2

(x^2+9)=2

Subtract 9 from each side

x^2 +9-9 = 2-9

x^2 = -7

Taking the square root of each side

sqrt(x^2) =sqrt(-7)

x = sqrt(-1 *7)

x = ±i sqrt(7)

A window is to be built in the shape of a rectangle surmounted by an isosceles triangle. The area of the window must be 6 square meters. Use Lagrange Multipliers to find the width and height of the rectangle for which the perimeter of the window will be as small as possible

Answers

Answer:

x = 2.536 m

y = 2 m

Step-by-step explanation:

Considering the three sides of the rectangle and the isosceles triangle

when resolving the width and height of the rectangle to achieve the smallest possible perimeter.

step 1 :

Area of window =  xy + 1/2 xz  , perimeter = x + 2y + 2c

c = [tex]\sqrt{z^2 + 1/4 x^2 }[/tex]

we are tasked with minimizing the perimeter ( p ) subject to A = 6

attached below is the detailed solution of the given problem

work for 12 hours and earn $140 find the unit rate

Answers

Answer:

11.60

Step-by-step explanation:

To find unit rate, you need to use the formula:

(amount of money) ÷ (amount of hours)

Since we have both, we can plug in

140 ÷ 12 will give you approximately 11.6

So, you receive $11.60 every hour.

What percentages of participants in the study were American?​

Answers

the percentage of the participants that were american is %15

I NEED HELP PLEASE!!!

Answers

I think it’s B. Hope this helps !!

A textbook store sold a combined total of 473 chemistry and sociology textbooks in a week. The number of sociology textbooks sold was 59 less than the number of chemistry textbooks sold. How many textbooks of each type were sold?

Answers

Answer:

I. C = 266 textbooks.

II. S = 207 textbooks.

Step-by-step explanation:

Let the chemistry textbook be C.

Let the sociology textbook be S.

Translating the word problem into an algebraic expression, we have;

C + S = 473 ..... equation 1

S = C - 59 ..... equation 2

Substituting eqn 2 into eqn 1, we have;

C + C - 59 = 473

2C - 59 = 473

2C = 473 + 59

2C = 532

C = 532/2

C = 266 textbooks.

Next, we would determine the value of S;

S = C - 59

S = 266 - 59

S = 207 textbooks.

Check:

C + S = 473

266 + 207 = 473

473 = 473

Ray’s weight increased by 11% in the last two years. If he gained 16.5 pounds, what was his weight two years ago?

Answers

Answer:

Ray weighed 150 pounds two years ago.

Step-by-step explanation:

11/100 = 16.5/x

11x = 16.5(100)

11x = 1,650

(11x)/11 = (1,650)/11

x = 150

About time that he should start going to the gym!

K.Brew sells a wide variety of outdoor equipment and clothing. The company sells both through mail order and via the internet. Random samples of sales receipts were studied for mail-order sales and internet sales, with the total purchase being recorded for each sale. A random sample of 18 sales receipts for mail-order sales results in a mean sale amount of $81.90 with a standard deviation of $22.25. A random sample of 8 sales receipts for internet sales results in a mean sale amount of $88.30 with a standard deviation of $23.25. Using this data, find the 90% confidence interval for the true mean difference between the mean amount of mail-order purchases and the mean amount of internet purchases. Assume that the population variances are not equal and that the two populations are normally distributed. Construct the 98% confidence interval.

Answers

Answer:

kdjdeoksndoddmsnsksndjdjd

The functions q and r are defined as follows

q(x)=-2x-2
r(x)=x^2+1
Find the value of r(q(4)).​

Answers

plug-in

-2(4) - 2

-8 - 2

-10

-10^2 + 1

-100 + 1

Your answer: -99

A well-known brokerage firm executive claimed that 60% of investors are currently confident of meeting their investment goals. An XYZ Investor Optimism Survey, conducted over a two week period, found that in a sample of 100 people, 69% of them said they are confident of meeting their goals. Test the claim that the proportion of people who are confident is larger than 60% at the 0.01 significance level.
The null and alternative hypothesis would be:________
a. H0:μ=0.6H0:μ=0.6
H1:μ≠0.6H1:μ≠0.6
b. H0:μ=0.6H0:μ=0.6
H1:μ<0.6H1:μ<0.6
c. H0:μ=0.6H0:μ=0.6
H1:μ>0.6H1:μ>0.6
d. H0:p=0.6H0:p=0.6
H1:p≠0.6H1:p≠0.6
e. H0:p=0.6H0:p=0.6
H1:p>0.6H1:p>0.6
f. H0:p=0.6H0:p=0.6
H1:p<0.6H1:p<0.6
The test is:________
a. two-tailed
b. left-tailed
c. right-tailed
The test statistic is:_______ (to 3 decimals)
The p-value is:_______ (to 4 decimals)
Based on this we:________
a. Fail to reject the null hypothesis
b. Reject the null hypothesis

Answers

We are testing a hypothesis. So, first we identify the null and the alternative hypothesis, then we find the test statistic, and with the test statistic, the p-value is found.

Null and alternative hypothesis:

Claim the the proportion is of 60%, thus, the null hypothesis is:

[tex]H_0: p = 0.6[/tex]

Test if the proportion is greater than 60%, thus, the alternative hypothesis is:

[tex]H_1: p > 0.6[/tex]

And the answer to the first question is given by option c.

Classification:

We are testing if the proportion is greater than a value, so it is a right-tailed test.

Test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

0.6 is tested at the null hypothesis:

This means that [tex]\mu = 0.6, \sigma = \sqrt{0.4*0.6}[/tex]

Survey, conducted over a two week period, found that in a sample of 100 people, 69% of them said they are confident of meeting their goals.

This means that [tex]n = 100, X = 0.69[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{0.69 - 0.6}{\frac{\sqrt{0.4*0.6}}{\sqrt{100}}}[/tex]

[tex]z = 1.837[/tex]

The test statistic is z = 1.837.

p-value:

The p-value of the test is the probability of finding a sample proportion above 0.69, which is 1 subtracted by the p-value of z = 1.837.

Looking at the z-table, z = 1.837 has a p-value of 0.9669.

1 - 0.9669 = 0.0331

The p-value is 0.0331.

Decision:

The p-value of the test is 0.0331 > 0.01, and thus:

a. Fail to reject the null hypothesis

For another example of a problem of a test of hypothesis, you can take a look at:

https://brainly.com/question/24166849

A study examines the relationship between being a registered nurse (yes/no) and passing a cultural competency exam (yes/no) among a group of 987 randomly selected employees at your hospital. What test would be appropriate to determine if there is an association

Answers

Answer:

The appropriate test to determine if there is an association between being a registered nurse and passing a cultural competency exam among a group of 987 randomly selected hospital employees is a:

Chi-square Test.

Step-by-step explanation:

The Chi-Square Test uses either a diagram (like a scatter plot) or a hypothesis test to show the existence of an association between two variables or statistically demonstrate that a relationship exists between the two variables.  Using the computed t-score, the significant association between two categorical variables can be measured and established.

If Jan can weed the garden in 2 hours and her husband can weed it in 1 hour and 30 minutes, find how long it takes them to weed the garden together.

Answers

Answer:

3 hours 30 minutes

Step-by-step explanation:

Jan :2 hours

her husband : 1 hour 30 minutes

2hr + 1 ½ hrs = 3 ½ hrs...that is 3 hours 30 minutes....?

The answer to the picture please

Answers

the required ans is 3√b+b/3b

If f(x) is an exponential function where f(-1.5) 26 and
f(5.5) = 7, then find the value of f(10), to the nearest hundredth.

Answers

Answer:

[tex]f(10) = 1147.25[/tex]

Step-by-step explanation:

Given

[tex]f(-1.5) = 26[/tex]

[tex]f(5.5) = 7[/tex]

Required

f(10)

An exponential function is represented as:

[tex]f(x) = ab^x[/tex]

[tex]f(-1.5) = 26[/tex] impleies that:

[tex]26 = ab^{-1.5}[/tex] --- (1)

[tex]f(5.5) = 7[/tex] implies that

[tex]7 = ab^{5.5}[/tex] --- (2)

Divide (2) by (1)

[tex]26/7 = ab^{-1.5}/ab^{5.5}[/tex]

[tex]3.71429 = b^{-1.5+5.5}[/tex]

[tex]3.71429 = b^{4}[/tex]

Take 4th root

[tex]b = 1.39[/tex]

Substitute [tex]b = 1.39[/tex] in [tex]26 = ab^{-1.5}[/tex]

[tex]26 = a * 1.39^{-1.5}[/tex]

[tex]26 = a * 0.6102[/tex]

Solve for (a)

[tex]a = 26/0.6102[/tex]

[tex]a = 42.61[/tex]

f(10) is calculated as:

[tex]f(10) = ab^{10}[/tex]

[tex]f(10) = 42.61 * 1.39^{10}[/tex]

[tex]f(10) = 1147.25[/tex]

If a house is worth $125,000 and depreciates by 7.5% per year, how much is it worth in two years

Answers

Answer:

Solution given;

principal [P]=$125,000

depreciated rate[R]=7.5%

time[t]=2 years

worth price of house [A]=???

we have

Worth price[A]=[tex]\large \bold P(1-\frac{R}{100})^{t}[/tex]

=[tex]125,000(1-\frac{7.5}{100})^{2}[/tex]

=125,000*0.925²

=125,000*0.855625

=106953.125

its worth price is $106953.125

Is this the correct answer?

Answers

Answer:

25.40

Step-by-step explanation:

tickets  ( 2 at 10.95 each) = 2* 10.95 = 21.90

popcorn ( 1 at 7.50)         = 7.50

Total cost before discount

21.90+7.50=29.40

subtract the discount

29.40-4.00 =25.40

Answer:

Yep! That's correct!

Step-by-step explanation:

We know that Marilyn and her sister are each getting a ticket that cost $10.95. They are also getting a $7.50 popcorn to share. Let's add those values up.

(10.95 * 2) + 7.50 {Multiply 10.95 by 2 to get 21.90.}

21.90 + 7.50 {Add 7.50 to 21.90 to get 29.40}

$29.40 (without the credit) in toal

A credit on a movie reward card functions as a discount, so what we need to do next is subtract 4 from 29.40. That will get us $25.40 as the total cost.

After doing the math, I can deduce that your answer is correct!

Mrs. Hanson has 3 pies for a party. She calculates that if she splits the pies evenly among the guests, they will each receive
1/6

of a pie. How many guests are there?

Answers

Answer:

18 guests.

Step-by-step explanation:

To find the number of guests, we can simply divide 1/6 from 3. The result gives us 18.

Determine the quadrant in which the terminal side of the given angle lies.
115°

Answers

Answer:

Quadrant 2

Step-by-step explanation:

Given

[tex]\theta = 115^o[/tex]

Required

The quadrant

We have:

[tex]0^o < \theta < 90^o[/tex] --- quadrant 1

[tex]90^o < \theta < 180^o[/tex] --- quadrant 2

[tex]180^o < \theta < 270^o[/tex] --- quadrant 3

[tex]270^o < \theta < 360^o[/tex] --- quadrant 4

So, by comparison; we have:

[tex]90^o < \theta < 180^o[/tex]

Substitute 115 for [tex]\theta[/tex]

[tex]90^o < 115 < 180^o[/tex]

The above is true for quadrant 2

Use the substitution methed to solve the system of equations. Choose the correct ordered pair.
2y+5x=13
2y+3x=5

Answers

Solve both equations for 2y :

2y + 5x = 13   ==>   2y = 13 - 5x

2y + 3x = 5   ==>   2y = 5 - 3x

Solve for x :

13 - 5x = 5 - 3x

8 = 2x

x = 4

Solve for y :

2y = 13 - 5×4

2y = -7

y = -7/2

As an ordered pair, the solution is then the point (x, y) = (4, -7/2).

A soccer team wants new uniforms. A jersey costs $42, shorts cost $26, socks cost $6, and shinguards cost $18. How much does one
uniform cost?
$62
$74
$83
$92

Answers

Answer:

$92

Step-by-step explanation:

42 + 26 + 6 + 18 = 92

In a residual plot against x that does NOT suggest we should challenge the assumptions of our regression model, we would expect to see a _____. a. parabolic band of points b. band of points having a slope consistent with that of the regression equation c. horizontal band of points centered near 0 d. widening band of points

Answers

Answer:

In a residual plot against x that does NOT suggest we should challenge the assumptions of our regression model, we would expect to see a _____.

c. horizontal band of points centered near 0

Step-by-step explanation:

This residual graph or plot shows the residual values (or the difference between the observed y-value (from scatter plot) and the predicted y-value (from regression equation line) on the vertical axis and displays the independent variable on the horizontal axis.  A linear regression model becomes appropriate for a dataset when the points are randomly dispersed around the horizontal axis near 0; otherwise, a nonlinear model becomes more appropriate.

f(x)=8x−4x+4 , then f(x−1)=

Answers

Answer: [tex]4x[/tex]

Step-by-step explanation:

[tex]f(x)=8x-4x+4\\f(x-1)=8(x-1)-4(x-1)+4\\f(x-1)=8x-8-4x+4+4\\f(x-1)=4x-8+4+4\\f(x-1)=4x[/tex]

Answer pleaseeeeeeeeee

Answers

Answer:

[tex]y=-\frac{8}{7}x+4[/tex]

Step-by-step explanation:

A line is perpendicular to another if its slope is the negative reciprocal of the other.

Your lines are in slope intercept form here, y=mx+b, where m is the slope. We can see the given line has slope [tex]\frac{7}{8}[/tex]. The negative reciprocal of that is [tex]-\frac{8}{7}[/tex], which is the slope of the third answer choice.

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