The number of pages per book on a bookshelf is normally distributed with mean 248 pages and standard deviation 21 pages. Using the empirical rule, what is the probability that a randomly selected book has less than 206 pages?

Answer:

54

Step-by-step explanation

You can't find the other sides, it may seem impossible, but you have to look at this problem in a different way. To find the perimeter of any figure you just need to know the top base, bottom base, right side, and left side.

We see that the top base equals to the bottom base as it is a rectilinear figure. You have to treat the side with 8 and side with 5 as one base. So they equal 13. Now do the same for the bottom.

So, 13 + 13 = 26

The right side is equal to the left side as it is a rectilinear figure, so the right side is 4 + 10 = 14. The left side is also 14.

So 14 + 14 = 28

26 + 28 = 54 units

Sorry, if I couldn't explain properly. I tried my best. As it is hard for me to explain in words. If I could draw it out, I could do better.

Answer:

45

Step-by-step explanation:

I broke the sections apart and then added:

14+14=28

13+13=26

26+28=54

Answer:

The equation has two zeros because the discriminant is greater than 0.

Step-by-step explanation:

3x^2 – 7x + 4

a=3   b = -7   c=4

The discriminant is

b^2 -4ac

(-7)^2 - 4(3)(4)

49 - 48

1

Since the discriminant is greater than zero, there are two real solutions

Answer:

The equation has two zeros because the discriminant is greater than 0.

Step-by-step explanation:

Answer:

Step-by-step explanation:

Imagine coordinate system

I quarter is where x>0 and y>0  {right top} and it is (0°,90°)

II quarter is where x<0 and y>0  {left top} and it is (90°,180°)

III quarter is where x<0 and y<0  {left bottom} and it is (180°,270°)

IV quarter is where x>0 and y<0  {right bottom} and it is (270°,360°)

Now, we have an angle wich vertex is point (0,0) and one of its sides is X-axis and the second lay at one of the quarters.

For the trig functons of an angle created by this second side always are true:

In first quarter all functions are >0

in second one only sine

in third one: tangent and cotangent

and in fourth one: cosine

{You can check this by selecting any point on the second side of angle and put it's coordinates to formulas of these functions:

[tex]\sin \phi=\dfrac y{\sqrt{x^2+y^2}}\,,\quad \cos \phi=\dfrac x{\sqrt{x^2+y^2}}\,,\quad \tan\phi=\dfrac yx\,,\quad \cot\phi=\dfrac xy[/tex]  }

So:

sinφ<0  ⇒ III or IV quarter

tanφ<0  ⇒ I or IV quarter

IV quarter  ⇒  φ ∈ (270°, 360°)

Answer:

2y+6x=180

Step-by-step explanation:

Because we know that side lengths BD, DC, and AD are all congruent, we can conclude that triangles BDA and CDA are congruent because they have at least two congruent sides. Since these triangles are both 45-45-90 triangles, angle C is equal to 45 degrees, or 3x. 45/3 is 15, so x=15. Angle B is equal to 45 degrees, or y, so y=45.

From there, we plug these numbers into the equation with 2(45) + 6(15), or 90+90 = 180.

Answer:

3(t-y)

Step-by-step explanation:

difference means subtractions

3*(t-y)

Answer:

3 × (t - y)

Step-by-step explanation:

three times = 3×

the difference between t and y = t - y

Now that we have separated the key information in the word expression, you can now piece together the expression.

3 × (t - y)

Hope this helped.

Answer:

-57

Step-by-step explanation:

the answer is -57 because if it is below sea level it is a negative but if it is above sea level it will be a positive

Answer:

x=4,  -5

Step-by-step explanation:

Factor and set each factor equal to zero

Answer:

X = -4 , x= 4

Step-by-step explanation:

20=x^2-x=0

-20+x^2+x=0

x^2+x-20=0

x×(x+5)-4(x+5)=0

(x+5)×(x-4)=0

x+5=0

×-4=0

x=-5

x=4

Answer:

x=16

Step-by-step explanation:

The angles indicated are alternate exterior angles and alternate exterior angles are equal when the lines are parallel

5x+28 = 7x-4

Subtract 5x from each side

5x+28 -5x = 7x-4-5x

28 = 2x-4

Add 4 to each side

28+4 = 2x-4+4

32 = 2x

Divide by 2

32/2 = 2x/2

16 =x

Step-by-step explanation:

(5x+28)=(7x-4)

2x=32

x=16

Answer:

C

Step-by-step explanation:

1 2/3*3 = about 5

5+1 2/3= 6 2/3<7 1/5

6 2/3+1 2/3 =8 1/3> 7 1/5

C is the best answer because it is the closest to the total amount of paint

Answer:

I believe the answer is A. 130

Answer:

A 130

Step-by-step explanation:

Answer:

1

Step-by-step explanation:

16-9=5t+2t

7=7t

1=t

Answer:

t = 1

Step-by-step explanation:

16 - 2t = 5t + 9

=> 16 - 2t - 9 = 5t

=> 16 - 9 = 5t + 2t

=> 7 = 7t

=> 7/7 = t

=> 1/1 = t

=> 1 = t

[tex]\\ \sf\longmapsto 8-6a-9a^2+27a^3[/tex]

[tex]\\ \sf\longmapsto 27a^30-9a^2-6a+8[/tex]

[tex]\\ \sf\longmapsto 3a(9a^2-3a-2)+8[/tex]

Answer:

A

Step-by-step explanation:

A logarithmic function, log(x) has a domain x>0. For this logarithmic equation x+2>0, x>-2.

Answer:

The answer is -½.

✌ yeah it is ✌

Answer:

(D) [tex]\begin{array}{*{20}c} {x=\frac{{ 5 \pm \sqrt {13} }}{{2}}} \end{array}[/tex]

Step-by-step explanation:

The quadratic formula is:

[tex]\begin{array}{*{20}c} {\frac{{ - b \pm \sqrt {b^2 - 4ac} }}{{2a}}} \end{array}[/tex]

Assuming that a is our x² term, b is our x term, and c is the constant, we can substitute inside the equation.

[tex]\begin{array}{*{20}c} {\frac{{ - (-5) \pm \sqrt {5^2 - 4\cdot1\cdot3} }}{{2\cdot1}}} \end{array}[/tex]

[tex]\begin{array}{*{20}c} {\frac{{ 5 \pm \sqrt {25 - 12} }}{{2}}} \end{array}[/tex]

[tex]\begin{array}{*{20}c} {\frac{{ 5 \pm \sqrt {13} }}{{2}}} \end{array}[/tex]

So the answer is D, [tex]\begin{array}{*{20}c} {x=\frac{{ 5 \pm \sqrt {13} }}{{2}}} \end{array}[/tex].

Hope this helped!

Answer:

The first term is 1

Step-by-step explanation:

The forward term to term rule is "multiply by 3 and add 1"

The backward rule is therefore

"subtract 1, then divide by three"

Apply the backward rule twice to go from 3rd to first term:

(13-1)/3 = 4

(4-1)/3 = 1

The first term is 1

Answer:

a_1 = 1

Step-by-step explanation:

your sequence is a_n = a_(n-1) * 3 + 1

if your 3rd one is 13 then:

a_3 = a_2 * 3 + 1 = (a_1 * 3 + 1) *3 + 1

13 = 9_a1 + 3 + 1

9 = 9*a_1

a_1 = 1 :)

Hi there!

[tex]\large\boxed{(n - 8)(n + 5)}[/tex]

n² - 3n - 40

Find two numbers that sum up to -3 and multiply into -40. We get:

-8, 5

Thus:

(n - 8)(n + 5)

hope this helps you understand the concept

Answer:

Find an integer k for which the roots of the equation will be rational and unequal. To find a value of k that makes the roots rational and unequal the discriminant must be greater than 0 and a perfect square.

Step-by-step explanation:

So if k=0 or k=5 the roots will be rational and unequal.  hope this helps you :)

Answer: False

The variable portions x^2y and xy^2 are slightly different, so that's why we don't have like terms here.

Answer:

False

Step-by-step explanation:

Like terms are those terms where they have the same variable

so here

5x2y variables are = 5x and 2y

7xy2 variables are = 7x and y2

you can observe that x variable is same but y variable is not same as 5x3y have 2y whereas 7xy2 have y2#

so the answer is FALSE

Answer:

When the plane makes its turn to fly southeast, it makes a 45º angle at point a, making angle abc also equal to 45º.  

Line ab is the 2 miles southeast the plane flies.

Line ac = line cb

sine (45º) = opposite / hypotenuse = cb / 2

.70711 = cb / 2

cb = 1.41422  miles = line ac

Line cs = 3 - 1.41422 = 1.58578

Line x^2 = cs^2 + cb^2

Line x^2 = 2.5146982084  + 2.0000182084

Line x^2 = 4.5147

Line x = 2.1248

Step-by-step explanation:

Answer:

The answer is below

Step-by-step explanation:

A rational number is a number in the form p/q where p and q are both integer numbers.

From the number line, each one unit is divided into six, therefore each one point is 1/6 unit. For the first number, it is between 0 and 1 and is on the fifth point, therefore the expression of the first number = 0 + 5(1/6) = 0 + 5/6 = 5/6

For the second number, it is between -1 and -2 and is on the third point, therefore the expression of the second number = -1 - 3(1/6) = -1 - 3/6 = -9/6

The difference between the two numbers is:

5/6 - (-9/6) = 5/6 + 9/6 = 14/6

Answer:

a. Fifty-seven thousand eight hundred and twenty-two hundredths < fifty-seven thousand eight hundred and three tenths

Step-by-step explanation:

In numbers it is written in the order

Th    H    Tens    Units    Decimal   Tenths   Hundredths  Thousandths

57    8      0          0          .                0             22

57     8      0         0          .                 3

This could be simply explained that the if we make compare the numbers before the decimal they are same but after the decimal we can analyze

3/10 and 22/100

Converting them into decimals we get

0.3 and 0.22

therefore 0.3 is greater than 0.22

so Choice a is only correct .

a. Fifty-seven thousand eight hundred and twenty-two hundredths < fifty-seven thousand eight hundred and three tenths

Answer: The person above me is correct

explanation:

I said that because i don't want no one saying that i copied them

Answer: [tex]x=-3/4[/tex]

Subtract 36x from both sides

[tex]20x-2-36x=36x+10-36x\\-16x-2=10[/tex]

Add 2 to both sides

[tex]-16x-2+2=10+2\\-16x=12[/tex]

Divide both sides by -16

[tex]\frac{-16x}{16} =\frac{12}{-16} \\x=\frac{-3}{4}[/tex]

Answer:

x = - [tex]\frac{3}{4}[/tex]

Step-by-step explanation:

Given

20x - 2 = 36x + 10 ( subtract 36x from both sides )

- 16x - 2 = 10 ( add 2 to both sides )

- 16x = 12 ( divide both sides by - 16 )

x = [tex]\frac{12}{-16}[/tex] = - [tex]\frac{3}{4}[/tex]

As a check

Substitute this value into the equation and if both sides are equal then it is the solution.

left side = 20 × - [tex]\frac{3}{4}[/tex] - 2 = - 15 - 2 = - 17

right side = 36 × - [tex]\frac{3}{4}[/tex] + 10 = - 27 + 10 = - x17

Since both sides are equal then x = - [tex]\frac{3}{4}[/tex] is the solution

Answer:

Option B.

Step-by-step explanation:

The measure of cage is 90 feet by 40 feet.

Length of rope [tex]=40\sqrt{2}[/tex] foot

It is clear that, length of rope is greater than one side of cage and raw a line which divides the cage in two parts as shown in below figure.

We need to find the shaded area.

By Pythagoras theorem:

[tex]hypotenuse^2=base^2+perpendicular^2[/tex]

[tex](40\sqrt{2})^2=(40)^2+perpendicular^2[/tex]

[tex]3200=1600+perpendicular^2[/tex]

[tex]3200-1600=perpendicular^2[/tex]

[tex]1600=perpendicular^2[/tex]

[tex]40=perpendicular[/tex]

So, it is a square.

From the figure it is clear that the shaded area contains 1/8th part of circle are half part of square.

Area of circle is

[tex]A_1=\pi r^2[/tex]

[tex]A_1=\pi (40\sqrt{2})^2[/tex]

[tex]A_1=3200\pi[/tex]

Area of square is

[tex]A_2=a^2[/tex]

[tex]A_2=(40)^2[/tex]

[tex]A_2=1600[/tex]

Area of shaded portion is

[tex]A=\dfrac{A_1}{8}+\dfrac{A_2}{2}[/tex]

[tex]A=\dfrac{3200\pi}{8}+\dfrac{1600}{2}[/tex]

[tex]A=400\pi+800[/tex]

[tex]A=400(\pi+2)[/tex]

The required area is [tex]400(\pi+2)[/tex] sq. ft.

Therefore, the correct option is B.

Answer:

Daily pay= $18

5 days pay = $90

Step-by-step explanation:

Archer's daily pay =p

Pay for 5 days= 5p

Gas = 1/2 of 5p

= 1/2 × 5p

= 5p/2

Water = $5

Balance = $40

5p = 5/2p + 5 + 40

5p - 5/2p = 45

10p -5p /2 = 45

5/2p = 45

p= 45÷ 5/2

= 45 × 2/5

= 90/5

P= $18

5p= 5 × $18

=$90

The equation to determine Archer's daily pay is

5p = 5/2p + 5 + 40

Divide both sides by 5

p = 5/2p + 45 ÷ 5

= (5/2p + 45) / 5

p= (5/2p + 45) / 5

Answer:

For Sprint

Cell phone plan would be;

$29.95 + $0.15n

For At & t

we have;

$4.95 + $0.39n

Step-by-step explanation:

Okay , here in this question, we are interested in creating equations for the cell phone plans.

Let’s start with Sprint

Sprint charges $29.95 monthly and $0.15 per text message.

Let the number of text messages sent be n

So the value of the cell phone plan will be;

$29.95 + $0.15(n) = $(29.95 + 0.15n)

For the At& t

Let the number of texts sent per month be n

The monthly plan is thus;

$4.95 + $0.39n

Answer:

D. take multiple samples to better estimate the true population average

Answer:

tbh im here for 5 points

Step-by-step explanation: