The length of a rectangle is 3 times the width, w. Which expressions represent the perimeter of the rectangle?

A - 4w
B - 7w
C - 8w
D - 5w + 2w
E - 2(3w + w)
F - 2(3w) + 2w

We have two types of textbooks. Let's use "x" to represent the number of math textbooks and "y" to represent the number of history textbooks.

Altogether, the bookseller sold 240 math and history textbooks. So:

x + y = 240

Now, the number of history textbooks sold was 72 less than the number of math books sold. So:

y = x - 72

Now we can substitute for y in the equation and solve:

x + y = 240

x + (x - 72) = 240

2x - 72 = 240

2x = 312

x = 156

The bookseller sold 156 math textbooks.

Since y = x - 72, he must have sold 84 history textbooks.

Let's check our answers:

x + y = 240

156 + 84 = 240

That is true, so we did get the correct answers.

Answer:

1) A

2) A

3) D

4) B

5) D

Step-by-step explanation:

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FACTS TO KNOW BEFORE SOLVING :-

If any 2 parallel lines are cut by a transversal line , then :-

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Q1)

According to the figure on the right side of the question paper ,

So,

∠7 + ∠8 = 180°

⇒ ∠2 + ∠8 = 180°    (∵ ∠2 = ∠7)

Hence , we can conclude that interior angles of same side are supplementary angles. So the correct option is A.

Q2)

According to the figure on the question paper ,

So ,

∠1 + ∠3 = 180°

⇒ ∠5 + ∠3 = 180°  (∵ ∠1 = ∠5)

Hence , we can conclude that exterior angles on the same side are supplementary angles. So , the correct option is A.

Q3)

According to the figure , (∠2 , ∠7) & (∠1 , ∠8) are alternate interior angles. But as (∠1 , ∠8) is there as an option , so the correct option is D.

Q4)

According to the figure , m∠1 = 129°.

Also , ∠1 & ∠7 are interior angles on the same side.

⇒ They are supplementary angles.

⇒ ∠1 + ∠7 = 180°

⇒ ∠7 = 180° - 129° = 51°

So , the correct option is B.

Q5)

According to the figure , m∠2 = 3x - 10 and m∠6 = 2x + 20

Also , ∠2 = ∠6 (∵ Corresponding angles are equal)

⇒ 3x - 10 = 2x + 20

⇒ 3x - 2x = 20 + 10

⇒ x = 30

So , ∠2 = 3×30 - 10 = 80° = ∠6 (∵ Corresponding angles are equal)

Hence , the correct option is D.

Answer:

Dude post it again lol

Step-by-step explanation:

The picture is so blurry

Answer:

17 cm

Step-by-step explanation:

Math STAAR Readiness 8 grade Quiz: The drawing below shows a side view of a picture frame on Mary’s desk.  Closest to the length of the frame support.

Answer:

17 or D

Step-by-step explanation:

a^2+b^2=c^2

4.2^2+16^2=c^2

17.64+25.6=c^2

c^2=273.64

c=√273.64

c=16.5 which can be rounded up to 17 or D

and I am reviewing for the math staar.

Answer:

30 degrees,30 degrees120, degrees

Step-by-step explanation:

The ratio of the angles is 1:1:4.

Let’s represent the angles by 1x, 1x, and 4x.

The sum of the interior angles of a triangle is 180°.

1x + 1x +4x = 180    Combine like terms.

           6 x = 180    Divide each side by 6

               x = 30°

1x=1*30=30 degrees

1x=1*30=30 degrees

4x=4*30=120 desgrees

Answer:

30, 30, 120

Step-by-step explanation:

Basic properties of a triangle:

The problem:

To solve:

Answer:

The 98% confidence interval for the mean magnesium ion concentration is between 122 ppm and 220 ppm. As the lower bound of the interval is below 195, it is not reasonable to conclude that the mean magnesium ion concentration may be greater than 195

Step-by-step explanation:

The six measurements are:

202, 164, 157, 177, 113, 213

Sample mean:

Sum of all values divided by the number of values which is 6. So

[tex]S_m = \frac{202+164+157+177+113+213}{6} = 171[/tex]

Sample standard deviation:

Square root of the difference squared between each value and the mean, and divided by 1 subtracted by the sample size. So

[tex]s = \sqrt{\frac{(202-171)^2+(164-171)^2+(157-171)^2+(177-171)^2+(113-171)^2+(213-171)^2}{5}} = 35.69[/tex]

Confidence interval

We have the standard deviation for the sample, which means that the t-distribution will be used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 6 - 1 = 5

98% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.98}{2} = 0.99[/tex]. So we have T = 3.365

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 3.365\frac{35.69}{\sqrt{6}} = 49[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 171 - 49 = 122 ppm

The upper end of the interval is the sample mean added to M. So it is 171 + 49 = 220 ppm

The 98% confidence interval for the mean magnesium ion concentration is between 122 ppm and 220 ppm. As the lower bound of the interval is below 195, it is not reasonable to conclude that the mean magnesium ion concentration may be greater than 195

Answer:

Step-by-step explanation:

[tex]sin ~a=\frac{12}{13} ,\frac{\pi}{2} <a<\pi\\a ~is~in~2nd~quadrant.\\sin~b=\frac{3}{5} ,0<b<\frac{\pi}{2} \\b~is~in~1st~quadrant.\\cos~b=\sqrt{1-sin ^2b} \\=\sqrt{1-(\frac{3}{5} )^2} \\=\sqrt{\frac{25-9}{25} } \\=\sqrt{\frac{16}{25} } \\=\frac{4}{5} ,\\cos~a=-\sqrt{1-sin^2 a} \\=-\sqrt{1-(\frac{12}{13} )^2} \\=-\sqrt{\frac{169-144}{169} } \\=-\sqrt{\frac{25}{169} } \\=-\frac{5}{13} \\cos(a-b)=cos~acos~b+sin~a sin~b\\=\frac{-5}{13}* \frac{4}{5} +\frac{12}{13}* \frac{3}{5} \\=?[/tex]

Answer:

75%

Step-by-step explanation:

[tex] \frac{27}{36} \times 100\%[/tex]

Answer:

$753.34

Step-by-step explanation:

trust me it is $753.34

Answer:

1 bowling ball

2 box

3 can

4 book

5 pyramid

Answer:

-1

Step-by-step explanation:

Answer:

$41, 863. 50

Step-by-step explanation:

$2000 - 6.5% = $1,993.50

$1,993.50 x 21 = $41, 863. 50

46 minutes is the elapsed time :)

Answer:

46 minutes

Step-by-step explanation:

In order to find the time elapsed, you must subtract 10:51 and 10:05 which equals 46 minutes.

Answer:

P' (-1,-4) N'(-5,0) U'(-2,1)

Step-by-step explanation:

Answer:

9 OR 1

Step-by-step explanation:

Let the number be x

x² - 10x = -9

x² - 10x + 9=0

a=1

b=-10

c=9

Solve using the quadratic formula

x =9 or 1

Answer:

1) x represents the # of cranes

  3x represents the # of cranes * 3 minutes

  10 represents the time the centerpiece took

  30 is the time limit

2) x[tex]x\geq \frac{20}{3} or 6\frac{2}{3}[/tex]

Btw, i'm not sure which way the signs go since I learned this a while ago.

Step-by-step explanation:

Good Luck!!!

Answer:

hope it helps...

Step-by-step explanation:

Answer:

y = ½x + 8

Step-by-step explanation:

The equation of the function can be written in the slope-intercept form y = mx + b.

m = slope = change in y/change in x

b = y-intercept = the value of y when x is zero

✔️From the table, when x = 0, y is 8.

Therefore,

y-intecept (b) = 8

✔️Find the slope (m) using two of the given pairs of values from the table, (-4, 6) and (2, 9):

m = (9 - 6)/(2 -(-4))

m = 3/6

m = ½

✔️Next is to plug in the values of m and b into y = mx + b.

Thus:

y = ½x + 8

9.5 ft

Step-by-step explanation:

trust in me pls I am serious this is the right answer

Answer:   (0.00027144,  0.00036176)

Step-by-step explanation:

The sample proportion of cell phone users who develop cancer of the brain or nervous system = [tex]\dfrac{133}{420027}=0.0003166[/tex]

Sample size : 420027

Confidence interval for p: [tex]\hat{p}\pm z^*\sqrt{\dfrac{\hat{p}(1-\hat{p})}{n}}[/tex], where [tex]\hat{p}[/tex]= sample proportion , n= sample size , z* = crirical z value.

For 90% confidence interval , z*= 1.645

Required confidence interval:

[tex]0.0003166\pm (1.645)\sqrt{\dfrac{0.0003166(1-0.0003166)}{420027}}\\\\=0.0003166\pm 0.00004516\\\\=(0.0003166-0.00004516,\ 0.0003166+ 0.00004516)\\\\=(0.00027144, \ 0.00036176)[/tex]

A ​90% confidence interval estimate of the percentage of cell phone users who develop cancer of the brain or nervous system = (0.00027144,  0.00036176)

Answer:

Area= 4y^2 + 14y + 12

Perimeter = 10y + 16

Step-by-step explanation:

Area of a reactangle = length × width

= (4y+6) × (y+2)

= 4y^2 + 6y + 8y + 12

= 4y^2 + 14y + 12

Perimeter of a rectangle = 2 × (a +b)

= 2 × ( 4y + 6 + y+ 2)

= 2 × ( 5y + 8)

= 10y + 16

[tex]\huge\red{\mid{\underline{\overline{\textbf{ANSWER}}}\mid}}[/tex]

A).28n rad/sec

Answer:

138.0700636942675[tex]\pi[/tex]

Step-by-step explanation:

Answer:D

Step-by-step explanation:

The effect of the time of day a science class is taught on test scores being studied in an experiment will be the length of the class period. The correct option is D.

A test score is a piece of data, typically a number, that describes how well a test-taker performed. It is "a summary of the evidence contained in an examinee's replies to the test items that are connected to the construct or constructs being tested," according to one formal definition.

Given that the effect of the time of day a science class is taught on test scores is being studied in an experiment.

The time of the class periods is affected by the length of the class period. The length of the class period of one subject should be optimum so that students get the concepts easily without getting bored.

Therefore, an effect of the time of day a science class is taught on test scores being studied in an experiment will be the length of the class period. The correct option is D.

To know more about a test analysis follow

https://brainly.com/question/22516544

#SPJ2

Answer:

y-4=3/2(x+4)

Step-by-step explanation:

If you plug the numbers into the equation (y-y1=m(x-x1)), you get y-4=3/2(x+4).

HOPE THIS HELPS

Answer:

By examining the line plot, we find the number with the maximum number of crosses or occurrences. This gives the mode of the data set. We find the smallest and the largest number from the data set and find their difference and this difference is the range of the given data set.

Step-by-step explanation:

Answer:

9

Step-by-step explanation:

We're using the Pythagorean theorem here since it's a right triangle.

a^2 (side) + b^2 (side) = c^2 (hypotenuse)

12 = a

x = b

15 = c

12^2 + b^2 = 15^2

144 + b^2 = 225

- 144             - 144 (subtracting 144 from both sides to isolate b)

b^2 = 81

[tex]\sqrt{b^2} = \sqrt{81}[/tex] (getting rid of the exponent by squaring both sides)

b = 9

x = 9