4 out of 5 phones that are recycled, have cracks on the screens. If 30 phones got recycled today, how many probably had cracks on their screens?

Answer:

B if I remember correctly.

Answer:

an observational study.

Step-by-step explanation:

An observational study can be defined as a type of study in which a researcher observes and measures the effect of a diagnostic test, risk factors, or treatments on individuals without intervening, changing or manipulating who are or aren't exposed to it (controlled conditions).

In this scenario, a sociologist reviews and analyzes a public park surveillance videos that were randomly selected over a period of several years. From the data obtained, he records the amount of time people spent on a smartphone. Thus, the statistical procedure the sociologist used is called an observational study because he doesn't interfere or manipulate the surveillance video containing information about the amount of time people in the public park spent on their smartphone.

Additionally, an unobtrusive data collection is a data collection technique used mainly in the social sciences to obtain or gather data without the researcher directly interfering or interfacing with the subject being studied. Thus, it doesn't influence the behavior, action or response of the subjects under study.

Answer:

36

Step-by-step explanation:

plug in a=3 for a

I belive you meant 99- 7 * a^2

so 99- 7 * (3)^2 = 36

The value of the expression  99 - 7a² for a = 3 is 36.

In mathematics, an expression that incorporates variables, constants, and algebraic operations is known as an algebraic expression.

The given expression is 99 - 7a².

Substitute a = 3 into the given expression:

99 - 7 (3)²

= 99 - 7×9

= 99 - 63

= 36

Hence, the value of the expression  99 - 7a² for a = 3 is 36.

Learn more about algebraic expressions here:

https://brainly.com/question/953809

#SPJ6

Answer:

88 Vegetarian Wraps Sold.

Step-by-step explanation:

This is a System of Equations Problem.

Your Two Systems Are:

v(1)+c(2.7)=244.6 and c+v=146

c = chicken wraps and v = vegetarian wraps

Each chicken wrap costs $2.70 (2.7). Put the variable of c next to (2.7) meaning to multiply.

Each vegetarian wrap costs $1 (1). Put the variable of v next to (1)

244.60 (244.6) is the total amount of money made from selling the wraps. This will be the total of the equation.

v(1)+c(2.7)=244.6

Solve 2.7c+v=244.6 for v.

Add -2.7c to both sides.

2.7c+v+−2.7c=244.6+−2.7c

v=−2.7c+244.6

Substitute −2.7c+244.6 for v in c+v=146.

c+v=146

c+−2.7c+244.6=146

Simplify both sides of the equation.

−1.7c+244.6=146

Add -244.6 to both sides.

−1.7c+244.6+−244.6=146+−244.6

−1.7c=−98.6

Divide both sides by -1.7.

[tex]\frac{-1.7c}{-1.7} =\frac{-98.6}{-1.7}[/tex]

c=58

Substitute 58 for c in v=−2.7c+244.6.

v=−2.7c+244.6

v=(−2.7)(58)+244.6

Simplify both sides of the equation.

v=88

Answer:

c=58 and v=88

88 vegetarian wraps were sold.

83.52

A

Step-by-step explanation:

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[tex]35,867[/tex] ✅

[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\orange{:}}}}}[/tex]

[tex]403 \times 89 \\ = 35,867[/tex]

[tex]\large\mathfrak{{\pmb{\underline{\orange{Happy\:learning }}{\orange{.}}}}}[/tex]

Answer:

35867 is the product of 409 and 89. At least I think so.

Step-by-step explanation:

Answer:

29.89%

Step-by-step explanation:

Step 1: We assume that 435 is 100% since it is our output value.  

Step 2: We next represent the value we seek with [tex]$x$[/tex].  

Step 3: From step 1, it follows that [tex]$100\%=435$[/tex].  

Step 4: In the same vein, [tex]$x\%=130$[/tex].  

Step 5: This gives us a pair of simple equations:  

[tex]100\%=435(1)\\\\x\%=130(2)[/tex]  

Step 6: By simply dividing equation 1 by equation 2 and taking note of the fact that both the LHS  (left-hand side) of both equations have the same unit (%); we have  

[tex]$\frac{100\%}{x\%}=\frac{435}{130}$[/tex]  

Step 7: Taking the inverse (or reciprocal) of both sides yields  

[tex]\frac{x\%}{100\%}=\frac{130}{435}\\\\\Rightarrow x=29.89\%[/tex]  

Therefore, [tex]$130$[/tex] is [tex]$29.89\%$[/tex] of [tex]$435$[/tex].

4 × ( 4 + 9 ) = 2 × ( 2 + x )

4 × 13 = 2 × ( 2 + x )

2 × 2 × 13 = 2 × ( 2 + x )

2 × 26 = 2 × ( 2 + x )

Divide both sides by 2

2 × 26 ÷ 2 = 2 × ( 2 + x ) ÷ 2

26 = 2 + x

Subtract both sides 2

26 - 2 = 2 - 2 + x

x = 24

Answer:

[tex]y = 2 \cos(4x) - 1 \\ when \: y = 0 \\ \cos(4x) = \frac{1}{2} \\ 4x = 60 \\ x = 15 \\ when \: x = 0 \\ y = 2 - 1 = 1 \\ intercepts = > (15, \: 0) \: and \: (0, \: 1) \\ midpoints : ( \frac{15 + 0}{2} , \: \frac{0 + 1}{2} ) \\ = (7.5, \: 0.5) \\ gradient = \frac{1 - 0}{0 - 15} \\ = - \frac{1}{15} \\ y = mx + c \\ at \: (7.5, \: 0.5) \\ 0.5 = - \frac{1}{15} \times 7.5 + c \\ 0.5 = - 0.5 + c \\ c = 1 \\ \therefore \: y = - \frac{1}{15} x + 1 \\ = > 15y = - x + 15[/tex]

Answer: [tex]45.11\ mph[/tex]

Step-by-step explanation:

Given

Speed R varies inversely with time T i.e.

[tex]R\propto \dfrac{1}{T}\\\\R=\dfrac{C}{T}\quad [\text{C=constant}][/tex]

when R=58 mph, T=7 s i.e.

[tex]58=\dfrac{C}{7}\quad \ldots(i)[/tex]

when T=9 s

[tex]R=\dfrac{C}{7}\quad \ldots(ii)[/tex]

Divide (i) and (ii)

[tex]\Rightarrow \dfrac{58}{R}=\dfrac{9}{7}\\\\\Rightarrow R=\dfrac{7}{9}\times 58\\\\\Rightarrow R=45.11\ mph[/tex]

Answer:

B

Step-by-step explanation:

Answer:

3520 Yards

Step-by-step explanation:

1 Mile = 1760 Yards

Answer: 3520 yards

Step-by-step explanation:

1 mile = 5280 x 2 = 10,560

2miles = 10,560

in yards = 3520 yards

Answer:

Option 1

Step-by-step explanation:

It's asking me to write 20 words so blah blah blah.

Answer:

ii) Find the percentage of boys/girls

Step-by-step explanation:

If im incorrect please comment here ------------》

Answer:

I = PRT where I is the interest, P is the principal deposited/borrowed, R is the rate as a decimal (take the number & divide by 100), and T is time in years.

Answer:

The answer is A :)) hehe.

Answer:

2.432 * 10⁹

Step-by-step explanation:

Given the expression;

3.8*10² × 6.4*10⁶

= (3.8*6.4)× (10²*10⁶)

= 24.32*10⁸

= 2.432* 10¹ * 10⁸

= 2.432 * 10⁹

Hence the product expressed as a scientific notation is 2.432 * 10⁹

Answer:

x=-6

Step-by-step explanation:

3-9= -6x+6x

x=-6

ans=-6

Given:

The figures cylinder, cube, cone, and pyramid.

To find:

The formula of volume for the given figures.

Solution:

Volume of a cylinder is:

[tex]V_1=\pi r^2h[/tex]

Where r is the radius and h is the height.

Volume of a cube is:

[tex]V_2=a^3[/tex]

Where a is side length of cube.

It is also written as:

[tex]V_2=l\times w\times h[/tex]

Where l is length, w is width, h is height and [tex]l=w=h[/tex].

Volume of a cone is:

[tex]V_3=\dfrac{1}{3}\pi r^2h[/tex]

Where r is the radius and h is the height.

Volume of a pyramid is:

[tex]V_4=\dfrac{1}{3}Bh[/tex]

Where B is the base area and h is the height.

Therefore the table of formulae is shown below:

Figure                       Volume formula

Cylinder                   [tex]\pi r^2h[/tex]

Cube                        [tex]l\times w\times h[/tex]

Cone                        [tex]\dfrac{1}{3}\pi r^2h[/tex]

Pyramid                    [tex]\dfrac{1}{3}Bh[/tex]

9514 1404 393

Answer:

  A.  54

Step-by-step explanation:

The two marked angles are "vertical angles," so are congruent.

  125° = (2x +17)°

  108 = 2x . . . . . . . . divide by °, subtract 17

  54 = x . . . . . . . . . . divide by 2

Answer:

x=54

Step-by-step explanation:

2x+17 will be kept equal to 125

so 2x+17=125

    2x=125-17

    2x=108

    x=[tex]\frac{108}{2}[/tex]

    x=54 ans

Answer:

y = (1/2)x + 16

Step-by-step explanation:

General point/slope form is

y = mx +b (the two points given are (4,18) and (16,24))

slope = rise/run = (24-18)/(16-4) = 6/12 = 1/2

y = (1/2)x + b

pick one point (4,18) and plug in

18 = (1/2)4 + b

18 = 2 + b

b = 16 (he still gets $16 for zero chores)

So

y = (1/2)x + 16

Answer:

1.) Adjacent and form a linear pair

2.) Adjacent and form a linear pair

3.) Adjacent

4.) Not adjacent

Hope this helps!

Answer:

1.) Adjacent and form a linear pair

2.) Adjacent and form a linear pair

3.) Adjacent

4.) Not adjacent

Answer:

x = -2 + 2√2 i and -2 - 2√2 i

Step-by-step explanation:

Given the function, y=-x^2+4x-12

x intercept occurs at y =  0

Substitute y = 0

0=-x^2+4x-12

x^2 - 4x + 12 = 0

Factorize

x = -4±√4²-4(12)/2

x = -4±√16-48/2

x = -4±√-32/2

x = -4 ± √32 i/2

x = -4+4√2 i/2 and x =-4-4√2 i/2

x = -2 + 2√2 i and -2 - 2√2 i

fraction form : 8/25

decimal form : 0.32

Answer:

8/25 or if you have to do decimal form it's 0.32

Step-by-step explanation:

Answer:

x = 12

Step-by-step explanation:

To solve this and show your work, you have to start of with the equation (3x - 6) = 30.

You then have to add 6 to both sides like this:

[tex](3x - 6) = 30 \\ \: \: \: \: \: \: \: \: \: \: + 6 \: \: \: \: \: + 6 [/tex]

So then the 6 is cancelled out, and you are left with

3x = 36.

Now you just have to divide both sides by 3 like this:

[tex] \frac{3x}{3} = \frac{36}{3} [/tex]

Which cancels 3 out, and you are left with

x = 12.

Answer:

The answer is "[tex](x + 8)^2 = 58[/tex]"

Step-by-step explanation:

Let the equation is:[tex]x^2+16x=-6[/tex]

by adding and subtracting 64 then:

[tex]x^2 + 16x + 64 = -6 + 64\\\\x^2 + 2\times x\times 8 + 64 = -6 + 64\\\\ (x + 8)(x + 8) = 58\\\\ (x + 8)2 = 58[/tex]

Answer:

y = 1/3x + 17/3

Step-by-step explanation:

6x + 2y = 8

2y = -6x + 8

y = -3x + 4

y = 1/3x + b

5 = 1/3(-2) + b

5 = -2/3 + b

17/3