The ratio of boys to girls in a classroom is 2 : 3. If there are
20 children in total, how many boys are there?

[tex] \frac{ {3}^{6} \times {5}^{3} }{ {9}^{2} \times {5}^{2} } \\ \\ \frac{ {3}^{6} \times {5}^{3 - 2} }{ {3}^{4} } \\ \\ {3}^{6 - 4} \times {5}^{1} \\ \\ {3}^{2} \times 5 \\ \\ 9 \times 5 \\ \\ 45.[/tex]

Answer:

As the sample size increases, the variability decreases.

Step-by-step explanation:

The actual departures from the mean are used to quantify variability. The variance would be lower the fewer the deviations.

By using the central limit theorem, we can determine that the sample mean for random samples of size n follows a normal distribution.

The standard deviation of the X bar will be [tex]\frac{s}{\sqrt{n} }[/tex].

where s is the sample's variance's square root.

As a result, we discover that the standard deviation, or variability, is inversely proportional to the square root of the sample size. Therefore, standard error lowers as sample size grows. The variability falls off as sample size rises.

Answer:

Yes

Step-by-step explanation:

Yes; points X and Y are fixed under the reflection, so they must lie on the line of reflection. Since two points determine a line, the line of reflection is XY.

https://www.rcboe.org/cms/lib010/GA01903614/Centricity/Domain/1030/Reflections.pdf

.

The geometry is that the number of sides for a 15- gon is 15 sides and the angles are 156° each.

The total angles in a 15 gon will be calculated as:

= (n - 2) × 180

= (15 - 2) × 180

= 2340

The value of each angle will be:

= 2340/15

= 156°

The total angles in a 16 gon will be calculated as:

= (n - 2) × 180

= (16 - 2) × 180

= 2520

The value of each angle will be:

= 2520/16

= 157.5°

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Answer:

A parallelepiped has three sets of four parallel edges; the edges within each set are of equal length. Parallelepipeds result from linear transformations of a cube (for the non-degenerate cases: the bijective linear transformations).

Step-by-step explanation:

A parallelepiped focuses on three-dimensional figures formed by six parallelograms.

A parallelepiped shape has the following features

Think of a cube or a cuboid.

Notice that they contain squares and rectangles

A parallelepiped is to a parallelogram as a square is to a cube and a rectangle to a cuboid

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Answer:

[tex]\fbox {Perimeter = 37.92}[/tex]

Step-by-step explanation:

Finding the missing side :

⇒ Take the tan value of the listed angle

⇒ tan 60° = √3 = 6/x

⇒ x = 6/√3 × √3/√3 = 2√3 = 2(1.73) = 3.46

Solving :

⇒ Perimeter = 10 + 2(6 + 3.46)

⇒ Perimeter = 10 + 2(9.46)

⇒ Perimeter = 19 + 18.92

⇒ Perimeter = 37.92

Answer:

look at the picture .

Step-by-step explanation:

look at the picture .

The simplified product of [tex]\frac{b- 5}{2b} X \frac{b^{2} + 3b }{b - 5}[/tex] is [tex]\frac{(b+3)}{2}[/tex]

The products can be simplified as follows;

Multiplying fraction,

[tex]\frac{x}{y} . \frac{a}{b} = \frac{xa}{yb}[/tex]

Therefore,

[tex]\frac{b- 5}{2b} X \frac{b^{2} + 3b }{b - 5} = \frac{(b-5)(b^{2} + 3b )}{(2b)(b-5)}[/tex]

Hence,

Let's reduce the fraction by dividing

[tex]\frac{b- 5}{2b} X \frac{b^{2} + 3b }{b - 5} = \frac{(b-5)(b^{2} + 3b )}{(2b)(b-5)} = \frac{(b^{2}+3b )}{(2b)}[/tex]

Therefore,

[tex]\frac{b- 5}{2b} X \frac{b^{2} + 3b }{b - 5} = \frac{(b-5)(b^{2} + 3b )}{(2b)(b-5)} = \frac{(b^{2}+3b )}{(2b)} = \frac{(b(b+3))}{2b}[/tex]

Hence,

[tex]\frac{b- 5}{2b} X \frac{b^{2} + 3b }{b - 5} = \frac{(b-5)(b^{2} + 3b )}{(2b)(b-5)} = \frac{(b^{2}+3b )}{(2b)} = \frac{(b(b+3))}{2b} = \frac{b+3}{2}[/tex]

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Answer:

A, b+3/2

Step-by-step explanation:

Answer:

3) r = 1.5

7) y = 18

11) x = -10

Step-by-step explanation:

3) Isolate the variable by dividing each side by factors that don't contain the variable.

7) Solve for y by simplifying both sides of the equation, then isolating the variable.

11) Move all terms that don't contain x to the right side and solve.

The differentiation of the function y = sin(2 sin⁻¹x) is; dy/dx = d√(1 - y²)]/(√1 - x²)

1) We want to differentiate the function;

[tex]\frac{\sqrt{x + 1} + \sqrt{x - 1}}{\sqrt{x + 1} - \sqrt{x - 1} }[/tex]

Differentiating this gives;

dy/dx = [tex]\frac{[(\frac{1}{2\sqrt{x + 1}} - \frac{1}{2\sqrt{x - 1}}) * \sqrt{x + 1} + \sqrt{x - 1}]}{(\sqrt{x + 1} - \sqrt{x - 1})^{2} }[/tex]

That can be simplified to get;

dy/dx = [tex]\frac{\sqrt{x + 1} + \sqrt{x - 1} }{(x - 1)\sqrt{x + 1} + (-x - 1) \sqrt{x - 1}}[/tex]

2) We want to differentiate the function;

y = sin(2 sin⁻¹x)

Differentiating the function gives;

dy/dx = [2cos(2 sin⁻¹x)]/√(1 - x²)

We know from trigonometric identity that;

cos²x = 1 - sin²x

Thus;

1 - sin²(2 sin⁻¹x) = cos²(2 sin⁻¹x)

But sin²(2 sin⁻¹x) = y²cos²(2 sin⁻¹x)

Thus; √(1 - y²) = cos(2 sin⁻¹x)

dy/dx = d√(1 - y²)]/(√1 - x²)

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Answer:

D

Step-by-step explanation:

The vertex is at (-2,4), so substituting into vertex form, only C and D match.

Also, the graph opens down, so the coefficient of x² is negative.

This eliminates C, leaving us with D

The total number of sugar will be 9/4.

The unitary method is a method for solving a problem by the first value of a single unit and then finding the value by multiplying the single value.

A Baker Had 1/3 Cups Of Sugar.

he Added 1/9 Cups To It

Let the number of sugar be x

x (1/3)  + 1/9x = 1

3x + 1x = 9

4x = 9

x = 9/4

Hence, the total number of sugar will be 9/4.

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The value of the give expression is  [tex]\frac{313}{748845}[/tex] OR 4.18 × 10⁻⁴

From the question, we are to determine the value of

2(5+34-67/45*43)^2

This can be written as

[tex]2 (\frac{5+34-67}{45 \times 43 })^{2}[/tex]

First, we will simplify the bracket

[tex]2 (\frac{-28}{1935 })^{2}[/tex]

Then, we get

[tex]2 \times \frac{-28}{1935 }\times \frac{-28}{1935 }[/tex]

= [tex]\frac{1568}{3744225}[/tex]

= [tex]\frac{313}{748845}[/tex] OR 4.18 × 10⁻⁴

Hence, the value of the give expression is  [tex]\frac{313}{748845}[/tex] OR 4.18 × 10⁻⁴

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Teniendo en cuenta la regla de tres simple, el cartero reparte 64.200 cartas en un semestre.

La regla de tres es una forma de resolver problemas de proporcionalidad entre tres valores conocidos y un valor desconocido, estableciendo una relación de proporcionalidad entre todos ellos.

Es decir, lo que se pretende con ella es encontrar el cuarto término de una proporción conociendo los otros tres.

Si la relación entre las magnitudes es directa, es decir, cuando una magnitud aumenta, la otra también (o cuando una magnitud disminuye, la otra también), se debe aplicar la regla de tres directa.

Para resolver una regla de tres directa se debe seguir la siguiente fórmula, siendo a, b y c datos conocidos y x la variable a calcular:

a ⇒ b

c ⇒ x

Entonces: [tex]x=\frac{cxb}{a}[/tex]

En este caso, se puede aplicar la regla de tres de la siguiente manera: Entonces, si el cartero en un mes reparte 10.700 cartas, ¿en 6 meses (un semestre) reparte cuántas cartas?

1 mes ⇒ 10.700 cartas

6 meses ⇒ ×

Entonces: [tex]cantidad de cartas=\frac{6 mesesx10.700 cartas}{1 mes}[/tex]

Resolviendo:

cantidad de cartas= 64.200 cartas

En resumen, el cartero reparte 64.200 cartas en un semestre.

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Answer:

Answer x=2/3, -1
Option B

Step-by-step explanation:

Answer:

B) x =( 2/3, -1)

Step-by-step explanation:

Equation:

[tex]6x {}^{2} + 2x = 4[/tex]

Solution:

We know that,

[tex] \rm \: Quadratic \: formula (x)=\cfrac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]

According to the problem,

Plugging them on the formulae,we obtain,

Choice B is accurate.

The permutation equation [tex]^{n+1}P_3 - ^nP_3= 3 * ^nP_2[/tex] is true for all integers n ≥ 3

We have:

[tex]^{n+1}P_3 - ^nP_3= 3 * ^nP_2[/tex]

Apply the following permutation formula

[tex]^{n}P_r = \frac{n!}{(n- r)!}[/tex]

So, we have:

[tex]\frac{(n + 1)!}{(n + 1 - 3)!} - \frac{n!}{(n - 3)!} = 3 * \frac{n!}{(n - 2)!}[/tex]

Evaluate the difference

[tex]\frac{(n + 1)!}{(n - 2)!} - \frac{n!}{(n - 3)!} = 3 * \frac{n!}{(n - 2)!}[/tex]

Expand

[tex]\frac{(n + 1)!}{(n - 2)(n - 3)!} - \frac{n!}{(n - 3)!} = 3 * \frac{n!}{(n - 2)(n - 3)!}[/tex]

Multiply through by (n - 3)!

[tex]\frac{(n + 1)!}{(n - 2)} - n! = 3 * \frac{n!}{(n - 2)}[/tex]

Expand

[tex]\frac{(n + 1) * n!}{(n - 2)} - n! = 3 * \frac{n!}{(n - 2)}[/tex]

Divide through by n!

[tex]\frac{(n + 1)}{(n - 2)} - 1 = \frac{3}{(n - 2)}[/tex]

Take the LCM

[tex]\frac{n + 1 - n + 2}{(n - 2)} = \frac{3}{(n - 2)}[/tex]

Evaluate the like terms

[tex]\frac{3}{(n - 2)} = \frac{3}{(n - 2)}[/tex]

Both sides of the equations are the same.

Hence, the permutation equation [tex]^{n+1}P_3 - ^nP_3= 3 * ^nP_2[/tex] is true for all integers n ≥ 3

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Answer:

X = 92 degrees

Step-by-step explanation:

the angles of a triangle all add up to 180 degrees, so 40 plus 180-132 = 88

180-88= 92 so X = 92

Answer:

8/15

Step-by-step explanation:

For right triangles tan p = opposite leg / adjacent leg

tan p = 24 /45   =   8/15

Answer:

C, D and E

Step-by-step explanation:

The numbers which are greater than given number are : -2, -1.5, and 1.25.

A fraction represents a part of a whole or, more generally, any number of equal parts.

Here, given number: -7/3

or we can write this as -2.33

Now, Converting option fraction value into decimal

A). -3

B) -5.5

C). -2

D). -1.5

E). 1.25

On comparing options from the given value we get

the number which are greater than -2.33;   -2, -1.5, and 1.25

Thus, the numbers which are greater than given number are : -2, -1.5, and 1.25.

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Using translation concepts, it is found that the type of transformation that triangle X′Y′Z′ undergoes is a reflection over the x-axis.

A translation is represented by a change in the function graph, according to operations such as multiplication or sum/subtraction in it's definition.

From triangle X′Y′Z′ to triangle X′′Y′′Z′′, the rule is given by:

(x,y) -> (x, -y)

Hence the type of transformation that triangle X′Y′Z′ undergoes is a reflection over the x-axis.

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It should be noted that a reflection is known as a flip and it's a mirror image of the shape.

An image will reflect through a line, known as the line of reflection.

Reflecting around x = 1 never touches the y coordinate, and the x coordinate transforms.

In other words, if a point were at x=π, it's distance to x=1 was π−1 so the new location is π−1 to the left of x=1.

The reflection is attached.

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Answer:

x² - 10x + 25

Step-by-step explanation:

The formula for squaring any binomial (an expression with two terms) is:

(a ± b)² = a² ± 2ab + b²

Let a = x and b = 5.

∴ Substituting:

   (x - 5)² = x² - 2(x)(5) + (-5)²

               = x² - 10x + 25

Answer:

10

Step-by-step explanation:

multiply -4 and 3 to get -12

multiply -12 and -2 to get 24

multiply 2 and 7 to get 14

multiply 14 and 1 to get 14

subtract 14 from 24 to get 10

Step-by-step explanation:

here I have done you can check it out

Answer:

The answer should be 3.3/4

Step-by-step explanation:

Answer:

b = 81

Step-by-step explanation:

given a² and b are directly proportional then the equation relating them is

a² = kb ← k is the constant of proportionality

to find k use the condition a = 2 when b = 9 , then

2² = 9k

4 = 9k ( divide both sides by 9 )

[tex]\frac{4}{9}[/tex] = k

a² = [tex]\frac{4}{9}[/tex] b ← equation of proportion

when a = 6 , then

6² = [tex]\frac{4}{9}[/tex] b

36 = [tex]\frac{4}{9}[/tex] b ( multiply both sides by 9 to clear the fraction )

324 = 4b ( divide both sides by 4 )

81 = b

Answer:

⇒   Let marked price be Rs.x.

⇒  Discount = 20% of marked price.

⇒  Discount=  

100

20

​  

×x=  

100

20x

​

⇒  Selling price = Marked price - Discount.

⇒  192=x−  

100

20x

⇒  192=  

100

80x

⇒  x=  

80

19200

=Rs.240

Answer:

S.p = 992

discount = 20%

marked price = S. p + discount

= 992 + 20/100*992

= 992 + 198.4

= 1190.4

The measure of angle D to the nearest tenth of a degree is 47 degrees

This theorem is used to determine the measure of sides and angles of a triangle.

According to the theorem

tan theta = opp/adj = 1.055

theta = arctan(1.055)

theta = 46.53 degrees

Hence the measure of angle D to the nearest tenth of a degree is 47 degrees

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