Please help.........

Answer:

20 girls

Step-by-step explanation:

boys: girls

3          5

There are 12 boys

12/3 = 4

Multiply each side by 4

boys: girls

3*4      5*4

12         20

Answer:

20 girls

Step-by-step explanation:

Divide 12 by 3 : 12/3 = 4

Multiply 4 by 5 : 4*5 = 20

Answer: 240 minutes

Step-by-step explanation:

Concept:

Here, we need to know the idea of unit conversion.

Unit conversion is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors.

1 hour = 60 minutes

Solve:

1 hour = 60 minutes

4 hours = 4 × 60 = 240 minutes

Hope this helps!! :)

Please let me know if you have any questions

Answer:

D Replace on equation with sum /difference of both equations

The systems are still the same

Step-by-step explanation:

5x + y = 3

4x - 7y = 8

Subtract the second equation from the first

5x + y = 3

-(4x - 7y = 8)

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

x    +8y = -5

The second equation in system B is the first equation in system a minus the second equation in system A

We added the same thing to each side of the equation so the the system is still the same

Answer:

464 $

Step-by-step explanation:

Answer:

The answer is 21.98. I just took area of the whole circle and subtracted it with the area of two circles in it

Answer:

21. 99

Step-by-step explanation:

[tex]s = \pi \times {r}^{2} \\ s1 = 3.14 \times 9 = 28.27 \\ s2 = 3.14 \times 1 = 3.14 \\ a = 28.27 - (3.14 \times 2) = 28.27 - 6.28 = 21.99[/tex]

Answer:

8. 72% × 850

= 72/100 × 850

= 72 × 8,5

= 612 ( b )

9. Poin B = 4 ( b )

Answer:

8. B

9. B

10. C

Step-by-step explanation:

8. To find 72% of 850, you would multiply 0.72 x 850. When you do that, it gives you 612.

9. B is on the number 4.

10. The expression is asking, "What is the absolute value of 28?". Absolute value means that the number inside will always be positive. For example, if it was -28, the absolute value would turn to 28. Since the question has 28 already positive, there is no change, so the answer would be 28.

Angles C and D are supplementary, or they add up to 180.

b = 180 - 75 - (180 - 127)

Hope this helps!

Answer:

Step-by-step explanation:

∠C + ∠D = 180   {Linear pair}

∠C + 127  = 180

           ∠C = 180 - 127

In ΔABC ,

∠A + ∠B + ∠C = 180   {angle sum property of triangle}

∠B = 180 - ∠A - ∠C

b = 180 - 75 - (180 - 127)

Answer:

Quadrant 4

Step-by-step explanation:

If the given angle was positive, then we go clockwise.

But it's negative so we go counterclockwise.

An alternative way of graphing

Quadrant 1 is 0-90°

Quadrant 2 is 90-180°

Quadrant 3 is 180-270°

Quadrant 4 is 270-360°

Subtract the given angle by 360 until no longer possible

750 - 360 = 390     390 - 360 = 30

Remember that this was originally a negative angle

Instead of going clockwise to quadrant 1, we go counterclockwise to quadrant 4, ending up at 330°

Answer:

3

Step-by-step explanation:

3 = 9 \:th \\ 1 = 3 \\ 3 \times 3 = 9 \\ 9 \div 3 = 3 \\ so \: that \: answer \: is \: 3

2=4x+y

y=2-4x

Александр Мазепов

Step-by-step explanation:

Step 1:  Solve for y

[tex]2 = 4x + y[/tex]

[tex]2 - 4x = 4x + y - 4x[/tex]

[tex]y = 2 - 4x[/tex]

Step 2:  Solve for x

[tex]2 - 2 - 4x = 0 - 2[/tex]

[tex]-4x / -4 = -2 / -4[/tex]

[tex]x = 1/2[/tex]

Step 3:  Solve for y

[tex]y = 2 - 4(0)[/tex]

[tex]y = 2[/tex]

Step 4:  Graph the equation

Graph the x-intercept, (1/2, 0), the y-intercept, (0, 2) and draw a line between them.  Look at the attached picture for the graph:

Answer:

Click the graph in Quadrant 1

Step-by-step explanation:

This graph is bigger in side length.

Let's use Gaussian elimination. Consider the augmented matrix,

[tex]\left[\begin{array}{ccc|ccc}1 & -1 & -1 & 1 & 0 & 0\\-1 & 2 & 3 & 0 & 1 & 0\\1 & 1 & 4 & 0 & 0 & 1\end{array}\right][/tex]

• Add row 1 to row 2, and add -1 (row 1) to row 3:

[tex]\left[\begin{array}{ccc|ccc}1 & -1 & -1 & 1 & 0 & 0\\0 & 1 & 2 & 1 & 1 & 0\\0 & 2 & 5 & -1 & 0 & 1\end{array}\right][/tex]

• Add -2 (row 2) to row 3:

[tex]\left[\begin{array}{ccc|ccc}1 & -1 & -1 & 1 & 0 & 0\\0 & 1 & 2 & 1 & 1 & 0\\0 & 0 & 1 & -3 & -2 & 1\end{array}\right][/tex]

• Add -2 (row 3) to row 2:

[tex]\left[\begin{array}{ccc|ccc}1 & -1 & -1 & 1 & 0 & 0\\0 & 1 & 0 & 7 & 5 & -2\\0 & 0 & 1 & -3 & -2 & 1\end{array}\right][/tex]

• Add row 2 and row 3 to row 1:

[tex]\left[\begin{array}{ccc|ccc}1 & 0 & 0 & 5 & 3 & -1\\0 & 1 & 0 & 7 & 5 & -2\\0 & 0 & 1 & -3 & -2 & 1\end{array}\right][/tex]

So the inverse is

[tex]\begin{bmatrix}1&-1&-1\\-1&2&3\\1&1&4\end{bmatrix}^{-1} = \boxed{\begin{bmatrix}5&3&-1\\7&5&-2\\-3&-2&1\end{bmatrix}}[/tex]

Answer:

The answer is C

Step-by-step explanation:

PLATO

Assuming the car's speed [tex]\frac{630}{14}=45\mathrm{mph}[/tex] does not change, the car will travel [tex]45\cdot42=\boxed{1890}[/tex] miles.

Hope this helps :)

Answer:

325 pencils, 650 markers, 975 pens.

Answer:

60

Step-by-step explanation:

15kilometers into 1 hour

60 minutes in 1 hour

so Amir ran 15 kilometers in 60 minutes

Answer:

0.25 km

step explanation:

that was the anwser on khan

Answer:

4 3/4 cups PLEASE MARK ME BRAINLIEST

Step-by-step explanation:

Bowl = 8 cups

Armando first used 2 1/2 cups of flour. So, we need to do 8 - 2 1/2.

8 - 2 1/2 = 8/1 - 5/2

Find the common denominator:

8/1 - 5/2 = 8 x 2/1 x 2 - 5 x 1/2 x 1 = 16/2 - 5/2

Find the final answer:

16/2 - 5/2 = 11/2 = 5 1/2

Then, Armando used 3/4 cups of sugar. So, we need to do 5 1/2 - 3/4.

5 1/2 - 3/4 = 11/2 - 3/4

Find the common denominator:

11/2 - 3/4 = 11 x 2/2 x 2 - 3 x 1/4 x 1 = 22/4 - 3/4

Find the final answer:

22/4 - 3/4 = 19/4 = 4 3/4

Finally, Armando used 1/3 cup of butter. So, we need to do 4 3/4 - 1/3.

4 3/4 - 1/3 = 19/4 - 1/3

Find the common denominator:

19/4 - 1/3 = 19 x 3/4 x 3 - 1 x 4/3 x 4 = 57/4 - 4/12

Find the final answer:

57/4 - 4/12 = 53/12 = 4 5/12

If u like my explanation then plz follow me for more solutions

Let x(t) denote the amount of salt (in kg) in the tank at time t. The tank starts with 18 kg of salt, so x (0) = 18.

The solution is drained from the tank at a rate of 90 L/min, so that the amount of salt in the tank changes according to the differential equation

dx(t)/dt = - (x(t) kg)/(9000 L) × (90 L/min) = -1/100 x(t) kg/min

or, more succintly,

x' = -1/100 x

This equation is separable as

dx/x = -1/100 dt

Integrating both sides gives

∫ dx/x = -1/100 ∫ dt

ln|x| = -1/100 t + C

x = exp(-1/100 t + C )

x = C exp(-t/100)

(a) Using the initial condition x (0) = 18, we find

18 = C exp(0)   ==>   C = 18

so that

x(t) = 18 exp(-t/100)

(b) After 20 minutes, we have

x (20) = 18 exp(-20/100) = 18 exp(-1/5) ≈ 14.74

so the tank contains approximately 14.74 kg of salt after this time.

Answer:

Step-by-step explanation:

A = (2)(3.14)(2)(4) + (2)(3.14)(2^2)

A = 75.36 in

Answer:

1/3

Step-by-stepi

Answer:

It's letter b

Step-by-step explanation:

I hope this help

We have,

[tex]a:b=3:6,a+b=96[/tex]

Introduce variable [tex]x[/tex] such that [tex]a=3x,b=6x[/tex]

The sum [tex]a+b=96[/tex] is therefore [tex]9x=96\implies x=10.\overline{6}[/tex]

So,

[tex]a=3\cdot10.\overline{6}=\boxed{32}[/tex] (sadia's age)

[tex]b=6\cdot10.\overline{6}=\boxed{64}[/tex] (father's age)

Hope this helps :)

Answer:

.73 per pound

Step-by-step explanation:

Take the total cost and divide by the number of pounds

4.38/ 6

.73 per pound

1099.56m² is the surface area of a cylinder that has a radius of 7 m and a height of 18 m.

Answer:

False

Step-by-step explanation:

To find the inverse of a function, switch the variables and solve for y.

The inverse of f(n)=-(n+1)^3:

[tex]y=-(n+1)^3[/tex]

[tex]n=-(y+1)^3[/tex]

[tex]\sqrt[3]{n} =-(y+1)[/tex]

[tex]\sqrt[3]{n} =-y-1[/tex]

[tex]\sqrt[3]{n} +1=-y[/tex][tex]-(\sqrt[3]{n} +1)=y[/tex]

[tex]-\sqrt[3]{n} -1=y[/tex]

Answer:

False

Step-by-step explanation:

Answer:

a. 1.44

Step-by-step explanation:

We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 40%.

At the null hypothesis, it is tested if the proportion is of at most 40%, that is:

[tex]H_0: p \leq 0.4[/tex]

At the alternative hypothesis, it is tested if the proportion is of more than 40%, that is:

[tex]H_1: p > 0.4[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

0.4 is tested at the null hypothesis:

This means that [tex]p = 0.4, \sigma = \sqrt{0.4*0.6}[/tex]

A random sample of 200 people was taken. 90 of the people in the sample favored Candidate A.

This means that:

[tex]n = 200, X = \frac{90}{200} = 0.45[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{0.45 - 0.4}{\frac{\sqrt{0.4*0.6}}{\sqrt{200}}}[/tex]

[tex]z = 1.44[/tex]

Thus the correct answer is given by option a.

9514 1404 393

Answer:

Step-by-step explanation:

In the parallelogram shown, angle B is the supplement of angle DAB:

  ∠B = 180° -77°37' = 102°23'

Angle ACB is the difference of angles 77°37' and 27°8', so is 50°29'.

Now, we know the angles and one side of triangle ABC. We can use the law of sines to solve for the other two sides.

  BC/sin(A) = AB/sin(C)

  AD = BC = AB·sin(A)/sin(C) = (169 lb)sin(27°8')/sin(50°29') ≈ 99.91 lb

 AC = AB·sin(B)/sin(C) = (169 lb)sin(102°23')/sin(50°29') ≈ 213.97 lb

I'm going to assume that you mean to say that i = √(-1) is a root of the auxiliary equation. That is, if the Cauchy-Euler DE is

x ²y'' + axy' + by = 0

then the auxiliary equation obtained by substituting y = xᵐ is

x ² (m (m - 1) xᵐ ⁻ ²) + ax (m xᵐ ⁻ ¹) + bxᵐ = 0

which reduces to

m (m - 1) + am + b = 0

or

m ² + (a - 1) m + b = 0

By the fundamental theorem of algebra, we can write the quadratic in terms of its roots r₁ and r₂,

(m - r₁) (m - r₂) = 0

Given that one root is the imaginary unit i, and the coefficients of the aux. equation are real, it follows that the other root is -i, because complex roots must occur with their conjugates. So we have as our aux. equation,

(m - i ) (m + i ) = 0

or

m ² + 1 = 0

Then a - 1 = 0 and b = 1, so that the given root and general solution correspond to the DE,

x ²y'' + xy' + y = 0