It takes 20 minutes for 5 people to paint 5 walls. How many minutes does it take 9 people to paint 9 walls

Answer:

Option D) multiply y by 4 in the first equation and subtract the second equation

Step-by-step explanation:

we have

2x+y=-10 ----> first equation

3x+4y=-20 ---> second equation

Verify each case

case A) multiply the first equation by 4 and subtract the second equation

so

(2x+y)*4=-10*4 ------> 8x+4y=-40

[8x+4y=-40]-[3x+4y=-20] -----> 5x=-20 -----> x=-4

This step is correct

case B) multiply the first equation by -4 and add the second equation

so

(2x+y)*-4=-10*-4 ------> -8x-4y=40

[-8x-4y=40]+[3x+4y=-20] ----->-5x=20 -----> x=-4

This step is correct

case C)  add 8 times the first equation and −2 times the second equation

so

(2x+y)*8=-10*8 ------> 16x+8y=-80

(3x+4y)*-2=-20*-2 ----> -6x-8y=40

[16x+8y=-80]+[-6x-8y=40] ----->10x=-40 -----> x=-4

This step is correct

case D) multiply y by 4 in the first equation and subtract the second equation

so

2x+4y=-10

[2x+4y=-10]-[3x+4y=-20] -----> -x=-10+20 -----> x=-10

This step is incorrect

NOT produce a system with the same solution

[tex]\bf \stackrel{5}{\boxed{1}\boxed{2}\boxed{3}\boxed{4}\boxed{5}}\stackrel{to}{\qquad }\stackrel{3}{\boxed{6}\boxed{7}\boxed{8}}\qquad \textit{ratio}[/tex]

The answer would be 31 inches long and 12 inches wide because you would subtract 36 - 5 and 24 - 12

Answer:

1. graph 4

2. graph 3

3. graph 1

4. graph2

Step-by-step explanation:

1. x- -2,-1,0,1,2

  y- 16,4,1,.25,.062

2. x- -2,-1,0,1,2

   y- .062,.25,1,4,16

3. x- -2,-1,0,1,2

   y- .25,.5,1,2,4

4- x- -2,-1.0,1,2

   y- 4,2,1,.5,.25

Answer:

1. graph 4

2. graph 3

3. graph 1

4. graph 2

Step-by-step explanation:

Answer:

1. Yes

2. No

3. No

4. No

By analyzing the sampling methods, we conclude that:

a) Yes.

b No

c) No

d) No

Here we need to analyze the given options.

a) The survey is given to random fans, the only thing connecting the fans is that all of them are fans of the team and all of them go to the arena, so there is some biasing, but the sample is random.

b) Here the fans decide if they want to answer or not, so this is more biased than the previous method.

c) This is also more biased than the first case, as these 80 persons also have in common the fact that they leave early.

d) Again, these 80 persons also have something in common, they could afford the best seats, so this is less random than the first option.

Then the answers are:

a) Yes.

b No

c) No

d) No

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Answer:

B. E. D. A. C

Step-by-step explanation:

The correct order of steps to determine the significance of results is:

B) Randomly separate the employees’ individual results into two groups.

E) Calculate the mean of each group.

D )Calculate the difference of the means.

A) Run the experiment many times.

C) Calculate the probability of a difference of 10.

Answer:  B) 3 out of 20

Step-by-step explanation:

[tex]\text{3 out of 30: }\dfrac{3}{30}=10\%\\\\\text{3 out of 20: }\dfrac{3}{20}=15\%\\\\\text{3 out of 15: }\dfrac{3}{15}=20\%\\\\\text{3 out of 12: }\dfrac{3}{12}=25\%[/tex]

The only option that results in 15% rotten apples is (B) 3 out of 20

Answer:

Choice C: approximately 121 green beans will be 13 centimeters or shorter.

Step-by-step explanation:

What's the probability that a green bean from this sale is shorter than 13 centimeters?

Let the length of a green bean be [tex]X[/tex] centimeters.

[tex]X[/tex] follows a normal distribution with

In other words,

[tex]X\sim \text{N}(11.2, 2.1^{2})[/tex],

and the probability in question is [tex]X \le 13[/tex].

Z-score table approach:

Find the z-score of this measurement:

[tex]\displaystyle z= \frac{x-\mu}{\sigma} = \frac{13-11.2}{2.1} = 0.857143[/tex]. Closest to 0.86.

Look up the z-score in a table. Keep in mind that entries on a typical z-score table gives the probability of the left tail, which is the chance that [tex]Z[/tex] will be less than or equal to the z-score in question. (In case the question is asking for the probability that [tex]Z[/tex] is greater than the z-score, subtract the value from table from 1.)

[tex]P(X\le 13) = P(Z \le 0.857143) \approx 0.8051[/tex].

"Technology" Approach

Depending on the manufacturer, the steps generally include:

For example, on a Texas Instruments TI-84, evaluating [tex]\text{normalcdf})(-1\text{E}99,\;13,\;11.2,\;2.1 )[/tex] gives [tex]0.804317[/tex].

As a result,

[tex]P(X\le 13) = 0.804317[/tex].

Number of green beans that are shorter than 13 centimeters:

Assume that the length of green beans for sale are independent of each other. The probability that each green bean is shorter than 13 centimeters is constant. As a result, the number of green beans out of 150 that are shorter than 13 centimeters follow a binomial distribution.

Let [tex]Y[/tex] be the number of green beans out of this 150 that are shorter than 13 centimeters. [tex]Y\sim\text{B}(150,0.804317)[/tex].

The expected value of a binomial random variable is the product of the number of trials and the probability of success on each trial. In other words,

[tex]E(Y) = n\cdot p = 150 \times 0.804317 = 120.648\approx 121[/tex]

The expected number of green beans out of this 150 that are shorter than 13 centimeters will thus be approximately 121.

Answer: It is shopping around for the best prices and saves money.

Step-by-step explanation: Bargain has the word "gain" in it. That's the best way I would look at it. Therefor I would cross out any other option that has to do with no benefit or the loss of something. Because we you bargain, you're getting multiple of something for a good price or maybe getting something that's on sale for a good price. For example: Buy 1 get 1 free items.

Answer:

B. cylinder

Step-by-step explanation:

Answer:

x = [tex]\frac{1}{4}[/tex]

Step-by-step explanation:

Using the rules of logarithms

• log[tex]x^{n}[/tex] ⇔ n logx

• logx - logy = log([tex]\frac{x}{y}[/tex])

• logx = logy ⇔ x = y

Given

2log2 - 3log2 = log2x

log2² - log2³ = log2x

log4 - log8 = log2x

log[tex]\frac{4}{8}[/tex] = log2x, hence

2x = [tex]\frac{1}{2}[/tex]

x = [tex]\frac{1}{4}[/tex]

Answer:

21

Step-by-step explanation:

21

The number that is impossible to divide by is 0, and your original number (X) cannot be 0 either. The possible values for your number are 11 and 22, and the corresponding numbers you divided it by are 1 and 2.

Let's assume the number you thought of is X, and the number you divided it by is Y. Based on the given information, we have the following equation:

X / Y = 11

To find the possible values for X and Y, we need to consider the factors of 11, which are 1 and 11. These factors provide us with potential pairs of X and Y:

X = 11 and Y = 1: When dividing 11 by 1, the result is indeed 11.

X = 22 and Y = 2: Dividing 22 by 2 gives us 11 as well.

So, the possible values for your number (X) are 11 and 22, and the corresponding numbers you divided it by (Y) are 1 and 2.

Now, let's discuss the numbers that are impossible to divide by or cannot be your original number. Any number divided by zero is undefined in mathematics. Hence, dividing by zero is not possible in this scenario. Therefore, the number 0 is impossible to divide by.

Additionally, your original number (X) cannot be 0. If X were 0, the equation would be:

0 / Y = 11

But any number divided by 11 is not equal to 0, which means X cannot be 0.

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Answer:

3.  x = 4, NOT extraneous

4. x=12, extraneous

Step-by-step explanation:

3. Solve for x, √(2x +1) = 3 and identify if it's an extraneous solution or not.

Since the square root is already isolated on its side, the first step is to put both sides to their square value to get rid of the square root.  We then get:

2x + 1 = 9  =>   2x = 8   =>   x = 4

To see if x = 4 is an extraneous solution, we enter it in the original equation and see if it works:

√(2x +1) = √(2 * 4 +1)  = √9 = 3

3  equals 3... so it's NOT an extraneous solution

4. Solve for x, -4√(x-3) = 12 and identify if it's an extraneous solution or not.

This time the square root isn't alone on its side yet... so we have to isolate it, by dividing each side by -4:

-4√(x-3) = 12 becomes √(x-3) = -3

Then we raise each side to their square value to get rid of the square root:

x - 3 = 9  which becomes x = 12

To see if x = 12 is an extraneous solution, we enter it in the original equation and see if it works:

-4√(x-3) = -4√(12-3) = -4√(9) = -4 (3) = -12

-12 does not equal 12... so it's an extraneous solution

Answer:

Step-by-step explanation:

The answer is D. I just did it.

Answer:

Option D.

Step-by-step explanation:

We have to solve the trigonometric expression give below.

[tex]tan(x+\frac{\pi }{3})[/tex]

[tex]=\frac{tanx+tan\frac{\pi }{3}}{1-tanx.tan\frac{\pi }{3}}[/tex]

[Since [tex]tan(a+b)=\frac{tana+tanb}{1-tana.tanb}[/tex]]

Now we place the value of [tex]tan\frac{\pi }{3}=\sqrt{3}[/tex]

[tex]=\frac{tanx+\sqrt{3}}{1-tanx\sqrt{3}}[/tex]

Therefore, option D. is the answer.

Answer:

two solutions x = 1 and x = - 8/3 x

Step-by-step explanation:

These are two questions and two answers:

Question 1:

A quadratic equation is shown below: 3x^2 − 15x + 20 = 0 Part A: Describe the solution(s) to the equation by just determining the radicand. Show your work.

Answer: The negative value of the radicand means that the equation does not have real solutions.

Explanation:

1) With radicand the statement means the disciminant of the quadratic function.

2) The discriminant is: b² - 4ac, where a, b, and c are the coefficients of the quadratic equation: ax² + bx + c

3) Then, for 3x² - 15x + 20, a = 3, b = - 15, and c = 20

and the discriminant (radicand) is: (-15)² - 4(3)(20) = 225 - 240 = - 15.

4) The negative value of the radicand means that the equation does not have real solutions.

Question 2:

Part B: Solve 3x^2 + 5x − 8 = 0 by using an appropriate method. Show the steps of your work, and explain why you chose the method used.

Answer: two solutions x = 1 and x = - 8/3x

Explanation:

1) I choose factoring (you may use the quadratic formula if you prefer)

2) Factoring

Given: 3x² + 5x − 8 = 0

Make 5x = 8x - 3x: 3x² + 8x - 3x - 8 = 0

Group: (3x² - 3x) + (8x - 8) = 0

Common factors for each group: 3x(x -1) + 8(x - 1) = 0

Coomon factor x - 1: (x - 1) (3x + 8) = 0

The two solutions are for each factor equal to zero:

x - 1 = 0 ⇒ x = 1

3x + 8 = 0 ⇒ x = -8/3

Those are the two solutions. x = 1 and x = - 8/3

Answer:

the answer is 21

Step-by-step explanation:

its 21 because 10+11=21

Answer:

2. distributive property

4. addition property of equality

5. addition property of equality

Hope this helps! :)

Answer:

The sum of the first 53 terms of the sequence is 3286

Step-by-step explanation:

* Lets talk about the arithmetic sequence

- There is a constant difference between each two consecutive numbers

Ex:

# 2  ,  5  ,  8  ,  11  ,  ……………………….

# 5  ,  10  ,  15  ,  20  ,  …………………………

# 12  ,  10  ,  8  ,  6  ,  ……………………………

* General term (nth term) of an Arithmetic Progression:

- U1 = a  ,  U2  = a + d  ,  U3  = a + 2d  ,  U4 = a + 3d  ,  U5 = a + 4d

- Un = a + (n – 1)d, where a is the first term , d is the difference

  between each two consecutive terms and n is the position of

  the term in the sequence

* Sum of an Arithmetic Progression:

  is calculate from  Sn = n/2[2a + (n - 1)d]

* Lets solve the problem

- The sequence is 140 , 137 , 134 , 131 , .........

∵ 137 - 140 = -3 and 134 - 137 = -3

∴ The sequence is arithmetic

- The first term a = 140

- The common difference d = -3

- n = 53

∵ Sn = n/2[2a + (n - 1)d]

∴ S53 = 53/2[2 × 140 + (53 - 1)(-3)]

∴ S53 = 53/2[280 + 52(-3) = 53/2[280 + -156] = 53/2[124]

∴ S53 = 3286

* The sum of the first 53 terms of the sequence is 3286

Answer:

S =3,286

Step-by-step explanation:

We are given the following sequence and we are to find the sum of the first 53 terms of this sequence:

[tex]140, 137, 134, 131, ...[/tex]

Finding the common difference [tex]d[/tex] = [tex]137-140[/tex] = [tex]-3[/tex]

[tex]a_1=140[/tex]

[tex]a_n=?[/tex]

[tex]a_n=a_1+(n-1)d[/tex]

[tex] a_n = 140 + (53 - 1 ) -3 [/tex]

[tex] a _ n = -16 [/tex]

Finding the sum using the formula [tex]S_n = \frac{n}{2}(a_1+a_n)[/tex].

[tex]S_n = \frac{53}{2}(140+(-16))[/tex]

S = 3,286

Answer:

The graph is symmetric about the x-axis only

Step-by-step explanation:

* Lets study the limacon curve

- Equations of the form:

# r = a + b sin θ

# r = a – b sin θ

# r = a + b cos θ

# r = a – b cos θ  

All will produce limacons.    

* Lets examine what happens for various values of a and b.  

- When the value of a is less than the value of b, the graph is  

 a limacon with and inner loop.

- When the value of a is greater than the value of b, the graph is

 a dimpled limacon.

- When the value of a is greater than or equal to the value of 2b,  

 the graph is a convex limacon.

- When the value of a equals the value of b, the graph is a special  

 case of the limacon.  It is called a cardioid.

* Notice that, in each of the graphs of the liamcons, changing

 from sine to cosine does not affect the shape of the graph just its  

 orientation.  

- Equations using sine will be symmetric to the vertical axis  

- Equations using cosine are symmetric to the horizontal axis.  

∵ r = -2 + 3 cos Ф

- from the notes up the equation of cosine is symmetric to

 the horizontal axis

∴ The graph is symmetric about the x-axis only

Answer:

Angle 8.

Step-by-step explanation:

It is equal to angle 8. These are called vertical angles in the States and opposite angles in the UK.

∠2 is equal to ∠8.

We need to find ∠2 is to which angle in the given figure.

Vertically opposite angles are angles that are opposite one another at a specific vertex and are created by two straight intersecting lines. Vertically opposite angles are equal to each other.

Here the vertically opposite angles are as follows:

∠2=∠8, ∠1=∠7, ∠3=∠5 and ∠6=∠4.

Therefore, ∠2 is equal to ∠8.

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Answer:

The percent of error in the measurement is 2%

Step-by-step explanation:

The percent of error associated with a reported measurement is calculate using the formula;

[tex]percenterror=\frac{error}{measurement}*100[/tex]

The error associated with a measurement is defined as half of the smallest unit of measurement used. The measurement reported was 2.5. The smallest unit of measurement for this reading is 0.1. The error is thus;

error = 0.1/2 = 0.05

The percent of error is thus;

[tex]\frac{0.05}{2.5}*100=2[/tex]

Answer:

2

Step-by-step explanation:

The compass was used to make the crossing arcs at point E and point B is labeled, so the next step would be :

A. Use a straight edge to draw a line through points B and E.

Option: A is the correct answer.

A.   Use a straightedge to draw a line through points B and E.

Perpendicular bisector--

It is a line that is perpendicular to the given line and the point where it intersects the given line segment is the mid-point of the line i.e. the perpendicular line bisects the line segment into  two equal parts.

Answer:

Step-by-step explanation:

pentagonal

Pentagonal pyramid is the type of pyramid.

A pentagonal pyramid in geometry is a pyramid with a pentagonal base and five triangular sides that intersect at a point. It has two sides, much like every pyramid. The lateral faces of the regular pentagonal pyramid are equilateral triangles, while the base is a regular pentagon.

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ANSWER

[tex]320.28 {cm}^{2} [/tex]

EXPLANATION

The surface area of a cylinder is given by

[tex]SA = 2\pi \: r(r + h)[/tex]

From the diagram, r=3cm and h =14cm.

We substitute the known values into the formula to get:

[tex]SA = 2\pi \: 3(3+ 14)[/tex]

[tex]SA = 2(3.14)\: 3(3+ 14) [/tex]

[tex]SA =320.28 {cm}^{2} [/tex]

The second choice is correct.

The probability of the gambler winning the jackpot is calculated using the hypergeometric distribution, dividing the number of favorable outcomes by the total outcomes.

The scenario describes a hypergeometric distribution because the gambler's selections are made without replacement. The total number of outcomes, i.e., possible ways to draw nine numbers from twelve, is given by combination C(12,9).

The gambler wins if all four selected numbers are among the drawn numbers, which is represented by the combination C(4, 4) and the remaining five numbers are from the eight not selected by the gambler, represented by C(8, 5). Therefore, the favorable number of outcomes is C(4,4)*C(8,5).

To calculate the probability that the gambler wins the jackpot, we divide the favorable outcomes by the total outcomes: P(win) =  [C(4,4)*C(8,5)] / C(12,9).

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The probability that the gambler wins the jackpot is: 0.0000092

To calculate the probability that the gambler wins the jackpot, we need to determine the total number of ways the casino can draw nine numbers from the first twelve positive integers and then divide this by the number of ways that the casino can draw nine numbers from the twelve positive integers without including any of the gambler's four selected numbers.

The total number of ways the casino can draw nine numbers from the first twelve positive integers is 12C9 = 220.

To calculate the number of ways that the casino can draw nine numbers from the twelve positive integers without including any of the gambler's four selected numbers, we first need to calculate the number of ways the casino can draw nine numbers from the eight positive integers that are not selected by the gambler. This is 8C9 = 8.

However, this does not take into account the order in which the numbers are drawn. Since the numbers are drawn without replacement, the order matters. Therefore, we need to multiply 8C9 by 9! to account for all the possible orderings of the nine numbers. This gives us 8C9 * 9! = 302,400.

Therefore, the probability that the gambler wins the jackpot is:

220 / (302,400 * 8) ≈ 0.0000092

Answer:

  12 cents

Step-by-step explanation:

(200 yd)·(3 ft/yd)·(0.02 ¢/ft) = 12 ¢

Answer:

C) 40% of 84

Step-by-step explanation

i don't know how to explain it T~T

The expression to estimate 36% of 84 is option D, 35% of 84, as it is the closest value to 36% that is also straightforward to calculate. Hence correct option D.

To estimate 36% of 84, you would want to choose the option that is closest to 36% without being too complicated to calculate quickly in your head. Among option A (30% of 84), option B (25% of 84), option C (40% of 84), and option D (35% of 84), the best estimate would be option D (35% of 84). This is because 35% is the closest value to 36% listed in the options and it would provide a reasonably accurate estimate that is easy to compute.

Answer:

144 (Answer B)

Step-by-step explanation:

We must do exponentiation first.  Next comes multiplication and division.  Last comes addition and subtraction.

the proper evaluation (not solution)  of  100 ÷ 5 × 4 + 4³ is as follows:

Evaluate 4³ first; it is 64.

Next, do the division:  20 · 4 + 64 = 80 + 64 = 144 (Answer B)

We know that there are 60 seconds in one minute

We know that it took Bob 55 minutes to clean the garage

The volume of a cube with a side length of 1 foot is 1 cubic foot, or 1728 cubic inches. So, 1 cubic foot is equal to 1728 cubic inches. The ratios of 1 cubic inch to 1/1728 cubic foot and 1 cubic foot to 1728 cubic inches can be used to convert between cubic inches and cubic feet.

When dealing with volumes, it's crucial to understand the relationship between cubic feet and cubic inches. Since 1 foot is equivalent to 12 inches, 1 cubic foot contains 12 × 12 × 12 = 1728 cubic inches. This conversion factor arises because volume is a measure of three-dimensional space, so each dimension is multiplied by itself three times.

To convert between cubic feet and cubic inches, you can use the conversion factor: 1 cubic foot = 1728 cubic inches. This means that to convert cubic feet to cubic inches, you multiply the volume in cubic feet by 1728, and to convert cubic inches to cubic feet, you divide the volume in cubic inches by 1728.

Understanding this relationship allows for easy conversion between the two units, whether you're dealing with measurements in feet or inches.

The probable question may be:

The volume of a cube with a side length of 1 foot is __ cubic foot, or __ cubic inches. So, 1 cubic foot is equal to __ cubic inches. The ratios of __ cubic inches to __ cublc foot and __ cubic foot to __ cubic inches can be used to convert between cubic inches and cubic feet.

Answer: [tex]128cm^2[/tex]

Step-by-step explanation:

You need to find the ratio of the area.

Knowing that the larger base of smaller trapezoid is 15 centimeters and the larger base of the larger trapezoid is 20 centimeters, you can find the ratio of the area:

[tex]r_{A}=(\frac{20cm}{15cm})^2\\\\r_{A}=\frac{16}{9}[/tex]

Then, to calculate the area of the larger trapezoid, you need to multiply the area of the smaller trapezoid by the ratio of the area.

Therefore you get that the area of the larger trapezoid is:

[tex]A_l=(r_{A})(A_s)\\\\A_l=(\frac{16}{9})(72cm^2)\\A_l=128cm^2[/tex]