Elena is conducting an experiment to determine if the high school students are more relaxed when the lights are off or when music is played during an exam. She selects 10 of her friends to take an exam with the lights off and another 10 of her friends to take an exam with music playing.

Required:
What is problematic about the way that Elena selected her groups?

Answer:

Step-by-step explanation:

no of men                                no of days

15                                             20

25                                            let be x

it is in indirect proportion

15/25=x/20

do cross multiplication

25*x=20*15

25x=300

x=300/25

x=12

therefore ot will take 12 day to complete the same wall by 25 men.  

Answer:

The equivalent angle on the first quadrant is 44º. On the second quadrant, it is the given angle of 146º.

The equivalent angle on the third quadrant is 214º.

The equivalent angle on the fourth quadrant is 316º.

Step-by-step explanation:

On the first quadrant:

The equivalent in the second quadrant of a angle on the first quadrant a is 180 subtracted by the angle, that is, 180 - a.

In this question, the reference angle is 146º, which is on the second quadrant.

So, on the first quadrant:

146 = 180 - a -> a = 180 - 146 = 44.

The equivalent angle on the first quadrant is 44º. On the second quadrant, it is the given angle of 146º.

Third quadrant:

The equivalent angle on the third quadrant is 2 multiplied by 180 and subtracted by the second quadrant angle. So

2*180 - 146 = 360 - 146 = 214º.

The equivalent angle on the third quadrant is 214º.

Fourth quadrant:

The equivalent angle on the fourth quadrant is 360 subtracted by the angle on the first quadrant. So

360 - 44 = 316º

The equivalent angle on the fourth quadrant is 316º.

Answer:

A(-3,4) B(1,-8)

y-y1/x-x1 =y2-y1/x2-x1

y-4/x--3 = -8-4/1--3

y-4/x+3 = -12/1+3

y-4/x+3 =-12/4

y-4/x+3 = -3

y-4 = -3(x+3)

y-4=-3x-9

y+3x +9-4=

y+3x+5=0

Answer:

y = -3x - 5

Step-by-step explanation:

-3, 4 and 1, -8

1 - -3 = 4

-8 - 4 = -12

[tex]\frac{-12}{4}[/tex] = [tex]\frac{-3}{1}[/tex] = -3

gradient/slope = -3

now substituting in the point -3, 4 to find the y intercept:

4= -3 x -3 + c

4 = 9 + c

-5 = c

y intercept = -5

equation is y = -3x - 5

Answer:

The margin of error is of 0.01.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1 - 0.7}{2} = 0.15[/tex]

Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].

That is z with a pvalue of [tex]1 - 0.15 = 0.85[/tex], so Z = 1.037.

The margin of error is of:

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

Standard deviation was 0.21.

This means that [tex]\sigma = 0.21[/tex]

Sample of 450:

This means that [tex]n = 450[/tex]

What is the margin of error, assuming a 70% confidence level, to the nearest hundredth?

[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]

[tex]M = 1.037\frac{0.21}{\sqrt{450}}[/tex]

[tex]M = 0.01[/tex]

The margin of error is of 0.01.

Answer:

[tex]x=19.67[/tex]cm

Step-by-step explanation:

Por Pitágoras,

[tex]x^{2} = 26^{2} - 17^{2} \\\\x^{2} = 676 - 289\\\\x^{2} =387\\\\x=\sqrt{387} \\\\x=19.67[/tex]

Answer:

they might not be the same numbers but you can do it with all of the step-by-step explanations I gave you just with the numbers you have

Step-by-step explanation:

Triangle ABC is a right angle triangle.

From the given right angle triangle,

AB represents the hypotenuse of the right angle triangle.

With m∠A as the reference angle,

AC represents the adjacent side of the right angle triangle.

BC represents the opposite side of the right angle triangle.

To determine tan m∠A, we would apply the tangent trigonometric ratio.

Tan θ = opposite side/adjacent side. Therefore,

Tan A = √32/2 = (√16 × √2)/2

Tan A = (4√2)/2

Tan A = 2√2

Answer:

x  =  28 m

y  =  14  m

A(max)  =  392 m²

Step-by-step explanation:

Rectangular garden    A (r ) =  x * y

Let´s call x the side of the rectangle to be constructed with a rock wall, then only one x side of the rectangle will be fencing with wire.

the perimeter of the rectangle is  p  =  2*x  +  2*y    ( but in this particular case only one side x will be fencing with wire

56   =   x    +  2*y      56   -  2*y  =  x

A(r)   =  ( 56  -  2*y ) * y

A(y ) =  56*y  -  2*y²

Tacking derivatives on both sides of the equation we get:

A´(y )  =  56  - 4 * y        A´(y) = 0     56  -  4*y  =  0    4*y  =  56

y =  14 m

and x  =  56  - 2*y    =  56 - 28  = 28 m

Then dimensions of the garden:

x  =  28 m

y  =  14  m

A(max)  =  392 m²

How do we know that the area we found is a local maximum??

We find the second derivative

A´´(y)  = - 4     A´´(y)  <  0   then the function A(y) has a local maximum at y = 14 m

Answer:

Number of tile need = 300 tiles

Step-by-step explanation:

Given:

Dimensions of floor = 3 m by 4 m

Perimeter of square tile = 80 cm

Find:

Number of tile need

Computation:

Perimeter of square tile = 4(Side)

80 = 4(Side of tile)

Side of tile = 80 / 4

Side of tile = 20 cm

Side of tile = 0.2 meter

Area of tile = 0.2 x 0.2

Area of tile = 0.04

Area of floor = 3 x 4

Side of tile = 12 square meter

Number of tile need = 12 / 0.04

Number of tile need = 300 tiles

Answer:59

Step-by-step explanation:

beacause you need to added them all together

Answer:

-46

Step-by-step explanation:

4(-8x + 5) = -32x - 26

-32x + 20 = -32x - 26

-32x + 32x = -26 - 20

x = -46

Answer:

-32x+20=-32x-26

20=-26

so unequal or undefined

hope this helps

have a good day :)

Step-by-step explanation:

Answer:

600 butter : 2000 flour : 200 sugar : 400 currants = 72 cakes

120 cakes could be made with 1 kg of butter

Step-by-step explanation:

Here, 72 cakes = 6 dozen cakes

( since 12 cake = 1 dozen cake ).

a. First calculate quantity of each ingredient per dozen by dividing each by 1.5 (18/12).

• Butter - 150/1.5 = 100 g per dozen

For 6 dozen :

100g x 6 = 600 g

• Flour - 500/1.5 = 333.33 g per dozen

For 6 dozen :

333.33 g x 6 = 2000 g

• Sugar - 50/1.5 = 33.33 g per dozen

For 6 dozen :

33.33 x 6 = 200 g

• Currants - 100/1.5 = 66.67 g per dozen

For 6 dozen :

66.67 x 6 = 400 g

b. It is given that,

150g butter is required to make = 18 cakes

Then by using unitary method, we get,

1 g of butter is required to make = 18/150 cakes

Since, 1 Kg = 1000 g

Then,

1000 g of butter is required to make = (18/150) × 1000

= 120 cakes

Hence, with 1 kg of butter 120 whole cakes can be made.

Hope this answer helps you :)

Have a great day :)

Mark brainliest

Answer:

The age of Sydney's is 46 and the age of Devaughn is 61

Step-by-step explanation:

Here;

Devaughn: 15yrs older that S..= 15+7= 22yrs old

sum of their age= 107

Now;

Sydney age= 107 - 100

7yrs old,,

Answer: 2 primes 1 disinct

Step-by-step explanation:

Answer:

(x + 4)² + (y - 7)² = 20²

Step-by-step explanation:

Graphing form

(x - h)² + (y - k)² = r²

(h, k) is the center = (-4, 7)

r is the radius = 20

-----------------------------------

Plug in the givens

(x + 4)² + (y - 7)² = 20²

Answer:

4 or....

Step-by-step explanation:

I think its 4. maybe not

Answer:

B) 204

Step-by-step explanation:

Rectangle 12 * 12 = 144

+

(2) Triangle A=h (b/2) = 12*(5/2) = 30 each

Answer:

It would be 0.41 ft^3

Step-by-step explanation:

Alright, to start, lets get the volume of the entire cinder block and the holes within it.

1.31 * 0.66 * 0.66 ---> 0.5706...

Next with the holes, they are both 0.33 wide, 0.39 long, and just as tall at 0.66 feet.

0.33 * 0.39 * 0.66 ---> 0.0849...

Since there's two of them: 0.1698...

To finish it, subtract the hole volume from the total volume;

0.5806 - 0.1698 = 0.4108

Rounds to 0.41 ft^3

Hi there! Use the difference of two squares formula below:

[tex] \large \boxed{ {x}^{2} - {y}^{2} = (x + y)(x - y)}[/tex]

You need to know that what number times itself and get 16. 16 comes from 4×4 or 4².

Then,

[tex] \large{ {x}^{2} - 16 = (x + 4)(x - 4)}[/tex]

[tex] \large{(x + 4)(x - 4) = 0}[/tex]

Solve the equation for all real values of x.

[tex] \large{x = 4, - 4}[/tex]

If you don't like using a formula. You can do this:

[tex] \large{ {x}^{2} - 16 = 0} \\ \large{ {x}^{2} = 16} \\ \large{x = \pm \sqrt{16} } \\ \large{x = \pm 4}[/tex]

If you remember the square root well, the square root of 16 is 4×4. Pull out the two 4's and thus the square root of 16 is 4.

For the square both sides method above (second method), we can define that:

[tex] \large \boxed{ \large{ {x}^{2} = a \longrightarrow x = \pm a }}[/tex]

Answer

Answer:

54°

Step-by-step explanation:

54°

Answer:

the missing angle is 54

Step-by-step explanation:

so first we need two triangle angles to get our measurement and we know straight lines add up to 180 so

180-123=57

57+69(other angle)=126

all triangle angles add up to 180 so subtract the two other angles to get your result

180-126=54

54 is your anwser

Answer:

Surface Area = 2×(10×7 + 10×4 + 7×4) = 276 feet^2

Step-by-step explanation:

Hope this helps :)

Answer:

your awnser would be [4, −6]

Step-by-step explanation:

hope this helps

Answer: Rs 7600

Step-by-step explanation:

The interest will be calculated as:

= Principal × Rate × Time

= 40000 × 5% × 4

= 40000 × 0.05 × 4

= 8000

Since he has to pay 5% of the total interest as tax for the bank, the amount that he will he get after 4 years will be:

= 8000 - (5% × 8000)

= 8000 - (0.05 × 8000)

= 8000 - 400

= 7600

Therefore, he'll get Rs 7600

Answer:

n=-17

Step-by-step explanation:

8(2n-5)=3(6n-2)

1) Distributive property

16x-40=18x-6

16x−40=18x−6

2) Subtract 16x16x from both sides.

-40=18x-6-16x

−40=18x−6−16x

3) Simplify 18x-6-16x18x−6−16x to 2x-62x−6.

-40=2x-6

−40=2x−6

4) Add 66 to both sides.

-40+6=2x

−40+6=2x

5) Simplify -40+6−40+6 to -34−34.

-34=2x

−34=2x

6) Divide both sides by 22.

-\frac{34}{2}=x

−

2

34

=x

7) Simplify \frac{34}{2}

2

34

to 17

−17=x

8) Switch sides.

x=−17

Given :

A man 1.30 m tall is on a top of a building. He observed a car on the road at an angle of 60 degrees if the building is 30 m high.

To Find :

How far is the car from the building.

Solution :

Let, distance between car and the building is x m.

So,

[tex]tan \ \theta = \dfrac{height\ of\ building + height\ of\ man}{distance \ between \ car \ and \ building}\\\\tan \ 60^o = \dfrac{30+1.3}{x}\\\\x = \dfrac{31.3}{1.73}\ m\\\\x = 18.09\ m[/tex]

Hence, this is the required solution.

I dont know Im sorry

Step-by-step explanation:

I just want points in not that smart

Hi there!

[tex]\large\boxed{y = \pm \sqrt{x - 16}}[/tex]

To solve for the inverse, swap the x and y variables:

x = y² + 16

Isolate for y by subtracting both sides by 16:

x - 16 = y²

Square root both sides:

√(x - 16) = y

Add the plus/minus sign:

y = ±√(x - 16)

Answer:

c

Step-by-step explanation:

1. 40°

2. 50°

3. 45°

4. a. draw a line from angle P to downward but make it so it can cut angle OPQ from the half

b. 70°

c. angle TPQ = angle OPQ ÷2

angle TPQ = 140÷2= 70°

Answer:

the correct answer is option B

Answer:

DE

Step-by-step explanation:

You can tell by the markings. Since there are two vertical markings it concludes that those sides are the same length.