In one city, 24% of adult smoke. In groups of size 130 of adults , what is the variance of the number that smoke ?

Answer:

Price before discount = $20 per keyboard

Price after discount = $18 per keyboard

Before the discount, you can buy 27 keyboards. After the discount, you can buy 30 keyboards.

===============================================

Work Shown:

k = cost of one keyboard before the price reduction

540/k = amount of keyboards purchased before the price reduction

k-2 = cost of one keyboard after the price reduction

540/(k-2) =  amount of keyboards purchased after the price reduction

540/(k-2) = (540/k) + 3

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If you multiply both sides by the LCM k(k-2), then you'll clear out the fractions and we can solve for k like so

540/(k-2) = (540/k) + 3

540k = 540(k-2) + 3k(k-2)

540k = 540k - 1080 + 3k^2 - 6k

0 = 540k - 1080 + 3k^2 - 6k - 540k

0 = 3k^2 - 6k - 1080

3k^2 - 6k - 1080 = 0

3(k^2 - 2k - 360) = 0

k^2 - 2k - 360 = 0

(k - 20)(k + 18) = 0

k-20 = 0 or k+18 = 0

k = 20 or k = -18

We ignore the negative result because a negative price doesn't make sense.

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

If k = 20, then

540/k = 540/20 = 27

Meaning that you can buy 27 keyboards before the price reduction

In other words, (27 keyboards)*(20 dollars per keyboard) = 540 dollars total.

After the price reduction, the cost per keyboard is now k-2 = 20-2 = 18

We can now buy 540/(k-2) = 540/18 = 30 keyboards, which is an increase of 30-27 = 3 extra keyboards. This helps confirm we have the correct answer.  

Answer:

$20

Step-by-step explanation:

X: the price of a keyboard

Y: number of keyboards to buy (original)

The shop owner spent $540 to purchase a stock of computer keyboards, so:

XY=540

⇒X=540/Y

If the price of each keyboard had been reduced by $2, he could have bought 3 more keyboards:

(X-2)(Y+3)=540  

⇒3X-2Y=6

⇒3.540/Y – 2Y=6

⇒Y=27

⇒X=20

⇒ the price of one keyboard: $20

Answer:

5 grams/metres squared = 50 kg/hectares

Step-by-step explanation:

We need to convert 5 grams/metres squared to kilograms/hectares.

We know that,

1 kg = 1000 g

1 hectare = 10000 m²

So,

[tex]5\ \dfrac{g}{m^2}=5\times \dfrac{0.001}{\dfrac{1}{10000}}\\\\=50[/tex]

Hence, 5 grams/metres squared = 50 kg/hectares

Answer:

she will make 78 dollars

Step-by-step explanation:

312 divided by 24 is `13

13 times 6 is 78

Answer:

[tex]\frac{x}{3} + \frac{1}{1} = \frac{x+3}{3}[/tex]

Step-by-step explanation:

[tex]\frac{x}{3} + \frac{1}{1} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ [ \ LCM \ of \ 1 , 3 = 3 \ ]\\\\= \frac{x}{3} + \frac{1 \times 3}{1 \times 3} \\\\= \frac{x}{3} + \frac{3}{3}\\\\=\frac{x+ 3}{3} \\\\[/tex]

Answer:

Step-by-step explanation:

Answer:

A picture of the graph is attached

Step-by-step explanation:

Answer:

5

Step-by-step explanation:

Let a = number of pieces of chocolate bought by Amin.

Let b = number of pieces of chocolate bought by Bob.

b = 2a

(a - 3)(b - 3) = 14

ab - 3a - 3b + 9 = 14

a(2a) - 3a - 3(2a) = 5

2a^2 - 3a - 6a = 5

2a^2 - 9a - 5 = 0

(2a + 1)(a - 5) = 0

2a + 1 = 0  or  a - 5 = 0

a = -1/2  or  a = 5

Amin cannot have bought -1/2 pieces of chocolate, so we discard the soluion a = -1/2.

a = 5

Answer: 5

Answer:

pretty sure its positive

Step-by-step explanation:

hope this helps, have  a great day!

Answer:

A is correct

Step-by-step explanation:

if we know that both x and y are positive, they are both going to be negative

and since we know that, -x divided by -y is the same as saying something negative divided by something negative which is ALWAYS positive because negatives cancel out leaving the answer positive something, something

Answer:

Step-by-step explanation:

The exponential decay function is

[tex]v(t)=a(b)^t[/tex] where b, the rate of decay, for us is (1 - .115) and a is the original value of the car which, for us, is 18000. t is the time in years. Using this information to write the equation we need to solve for the value when the car is 10 years old:

[tex]v(t)=18000(.885)^t[/tex] and we sub in 10 for t:

[tex]v(t)=18000(.885)^{10[/tex] which simplifies to

v(t) = 18000(.2947356754) so

v(t) = 5305.24

Answer:

Each student gets 1.75 ft of ribbon

Step-by-step explanation:

r × 4 = 7

First, divide the given factor by itself in order to get the variable by itself.

4 ÷ 4

Next, divide the product by the given factor bc what you do to the left, you must do to other side.

7 ÷ 4

Last, right down your new equation and find you solution.

New Equation: r = 1.75

Answer:

Step-by-step explanation:

Answer:

Option C

Step-by-step explanation:

Barrel (storage container) is enclosed in a small square fence.

Since, barrel is touching the surfaces from four sides of the cylindrical barrel.

Length of each side of the square fence = Diameter of the barrel

                                                                   = 2(radius of the barrel)

                                                                   = 2(1.5)

                                                                   = 3 feet

Perimeter of a square = 4(Side of a square)

                                     = 4(3)

                                     = 12 feet

Therefore, Option C will be the correct option.

Answer:

240 degrees

Step-by-step explanation:

360 - 120 = 240

Answer:

240° i think

Answer:

D

Step-by-step explanation:

To find the inverse of a function, first replace f(x) with y.

Next, switch all the x's and y's, and then solve for y.

Finally, replace y with f-1(x).

Answer:

39

Step-by-step explanation:

Answer:

16

Step-by-step explanation:

f(x) = (-4 + x)^2

Let x=8

f(8) = (-4 + 8)^2

Parentheses  first

     = 4^2

Then powers

    = 16

Hi there!

[tex]\large\boxed{\text{Gradient = -1}}[/tex]

We can find the slope using the slope formula:

Slope = (y2-y1)/(x2-x1)

Plug in the given coordinates:

Slope = (1 - 5)/(7 - 3)

Simplify:

Slope = -4/4

Slope = -1

Answer:

10

Step-by-step explanation:

When multiplying numbers of the same base the exponents are added

therefor

n + 10 = 20

n = 10

Answer:

10

Step-by-step explanation:

y^n × y^10 = y^20

y^(n+10) = y^20

n+10 = 20

n = 20-10

n = 10

Answer:

hiii my pic lol (✿^‿^)(✿^‿^)(✿^‿^)(✿^‿^)

Answer:

Two real distinct solutions

Step-by-step explanation:

Hi there!

Background of the Discriminant

The discriminant [tex]b^2-4ac[/tex] applies to quadratic equations when they are organised in standard form: [tex]ax^2+bx+c=0[/tex].

All quadratic equations can be solved with the quadratic formula: [tex]x = \frac{{ - b \pm \sqrt {b^2 - 4ac} }}{{2a}}}[/tex].

When [tex]b^2-4ac[/tex] is positive, it is possible to take its square root and end up with two real, distinct values of x.

When it is zero, we won't be taking the square root at all and we will end up with two real solutions that are equal, or just one solution.

When it is negative, it is impossible to take the square root and we will end up with two non-real solutions.

Solving the Problem

[tex]3x^2+5x=-1[/tex]

We're given the above equation. It hasn't been organised completely in [tex]ax^2+bx+c=0[/tex], but we can change that by adding 1 to both sides to make the right side equal to 0:

[tex]3x^2+5x+1=0[/tex]

Now that we can identify the values of a, b and c, we can plug them into the discriminant:

[tex]D=b^2-4ac\\D=(5)^2-4(3)(1)\\D=25-4(3)(1)\\D=25-12\\D=13[/tex]

Therefore, because the discriminant is positive, the equation has two real, distinct solutions.

I hope this helps!

Answer:

There is the graph of money made to cars sold

The Graph is provided in the below image.

Slope and y-intercept are used to graph an equation in the following ways:

To solve the question we follow the steps in the given instructions.

Learn more about graphs here-

brainly.com/question/16608196

#SPJ2

Answer:

The answer is "Option A"

Step-by-step explanation:

Using the range difference to calculate the maximum and minimum value.

The range of the chinstrap penguins are:  

[tex]R(c) = Max(c) - Min(c) = 13.2[/tex]

The range of the Gentoo penguins are:

 [tex]R(g) = Max(g) - Min(g) = 15.4[/tex]

For point A:

[tex]Max(c) = x\\\\Max(g) = x + 5.8\\\\R(c) = x - Min(c) = 13.2 \to x = 13.2 + Min(c)\\\\R(g) = x + 5.8 - Min(g) = 15.4 \to x = 9.6 + Min(g)[/tex]

equate both of them

[tex]13.2 + Min(c) = 9.6 + Min(g)Min(g) - Min(c) = 3.6[/tex]

It indicates that Min(c) surpasses Min(g), whereas Max(g) exceeds Max (c).

Therefore, the Max is picked for g for all penguins and the minimum is picked for c.    

Range of all penguins [tex]= Max(g) - Min(c) = x + 5.8 - x + 13.2 = 19[/tex]

Therefore, it will be determined as the option.

For point B:

In estimating the range the median height cannot help.

For point C:

In order to calculate the variety, the connection between both the mean height cannot be sued.

Answer:

24a²-73ab+24b²

Step-by-step explanation:

(8a - 3b) (3a - 8b) =

24a²-64ab-9ab+24b²

= 24a²-73ab+24b²

Answer:

V = 1372cm3

Step-by-step explanation:

See the image above

Answer:

Step-by-step explanation:

Substitute values into given equation and solve for P(t):

Answer:

x = 3 + [tex]\sqrt{3}[/tex] , 3 - [tex]\sqrt{3}[/tex]

Step-by-step explanation:

(2x-3)(x-2) + (x9x-2) = (x)(2x-3)

(2x-3)(x-2)+x(x-2)=x(2x-3)

(2x-3)(x-2)=x(2x-3)-x(x-2)

2x^2 -4x = x(2x-3 - x -2)

2x^2 - 7x + 6 = x^2 - x

[tex]x^{2}[/tex] - 6x + 6 = 0

use quadratic equation to get to final answer

-b +- [tex]\frac{-b+\sqrt{b^{2} -4ac } }{2a} , \frac{-b-\sqrt{b^{2} -4ac } }{2a} where a = 1 b = -6 and c= 6[/tex]

Answer:

Step-by-step explanation:

the formula is C=2√πA

so simplifying that would give us c=2(4π)

simplify again and we get c=8π

Answer:

6

Step-by-step explanation:

To find how many perennials there are, multiply the amount of plants by the percent of perennials. When you multiply percents, just put the percent behind the decimal

60x0.35=21

There are 21 perennials

Do the same for the biennials:

60x0.25=15

Therefore 15 biennials

Subtract the amount of perennials from the amount of biennials

21-15=6

There is 6 more perennials than biennials

Answer:

the answer is 6

21-15=6

Step-by-step explanation.

35% of 60 = 21 for perenalis

25% of 60 = 15 for biennials

40% of 60 = 24 for annuals

Answer:

The maximum height that the stone reaches is of 26 feet.

Step-by-step explanation:

Vertex of a quadratic function:

Suppose we have a quadratic function in the following format:

[tex]f(x) = ax^{2} + bx + c[/tex]

It's vertex is the point [tex](x_{v}, y_{v})[/tex]

In which

[tex]x_{v} = -\frac{b}{2a}[/tex]

[tex]y_{v} = -\frac{\Delta}{4a}[/tex]

Where

[tex]\Delta = b^2-4ac[/tex]

If a<0, the vertex is a maximum point, that is, the maximum value happens at [tex]x_{v}[/tex], and it's value is [tex]y_{v}[/tex].

y = -2x2 + 8x + 5

Quadratic function with [tex]a = -2, b = 8, c = 5[/tex]

What is the maximum height that the stone reaches?

y value of the vertex. So

[tex]\Delta = 8^2-4(-2)(5) = 64 + 40 = 104[/tex]

[tex]y_{v} = -\frac{104}{4(-2)} = 26[/tex]

The maximum height that the stone reaches is of 26 feet.