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2 years ago

WILL MARK BRAINLIEST!!!

Mathematics

2 answers:

denis23 [38]2 years ago

6 0

Answer:

Okay the question is a little unclear, but if he's only doing english, science and history the answer should be  17/40

Step-by-step explanation:

1/5=8/40

3/8=15/40

8/40+15/40=23/40

40/40-23/40=17/40

attashe74 [19]2 years ago

4 0

ANSWER:

Study time for english = 1/5.
Study time for science = 3/8.

We will first equate the denominator of the fractions.

So, 1/5 × 8/8 = 8/40

3/8 × 5/5 = 15/40

8/40 + 18/40 = 23/40

Total time = 40/40 = 1.

So for history work, he used

40/40 - 23/40
17/40.

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The accompanying data on x = current density (mA/cm2) and y = rate of deposition (m/min)μ appeared in a recent study.

gtnhenbr [62]

Answer:

a) $r=\frac{4(333)-(200)(5.37)}{\sqrt{[4(12000) -(200)^2][4(9.3501) -(5.37)^2]}}=0.9857$

The correlation coefficient for this case is very near to 1 so then we can ensure that we have linear correlation between the two variables

b) $m=\frac{64.5}{2000}=0.03225$

Now we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{200}{4}=50$

$\bar y= \frac{\sum y_i}{n}=\frac{5.37}{4}=1.3425$

$b=\bar y -m \bar x=1.3425-(0.03225*50)=-0.27$

So the line would be given by:

$y=0.3225 x -0.27$

Step-by-step explanation:

Part a

The correlation coeffcient is given by this formula:

$r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}$

For our case we have this:

n=4 $\sum x = 200, \sum y = 5.37, \sum xy = 333, \sum x^2 =12000, \sum y^2 =9.3501$

$r=\frac{4(333)-(200)(5.37)}{\sqrt{[4(12000) -(200)^2][4(9.3501) -(5.37)^2]}}=0.9857$

The correlation coefficient for this case is very near to 1 so then we can ensure that we have linear correlation between the two variables

Part b

$m=\frac{S_{xy}}{S_{xx}}$

Where:

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}{n}$

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=12000-\frac{200^2}{4}=2000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=333-\frac{200*5.37}{4}=64.5$

And the slope would be:

$m=\frac{64.5}{2000}=0.03225$

Now we can find the means for x and y like this:

$\bar x= \frac{\sum x_i}{n}=\frac{200}{4}=50$

$\bar y= \frac{\sum y_i}{n}=\frac{5.37}{4}=1.3425$

And we can find the intercept using this:

$b=\bar y -m \bar x=1.3425-(0.03225*50)=-0.27$

So the line would be given by:

$y=0.3225 x -0.27$

4 0

3 years ago

What is the constant of proportionality for m=32•g

lina2011 [118]

Answer:

∴ Constant of Proportionality is 32

Step-by-step explanation:

Here Given;

$m=32\times g$ (equation-1)

$\frac{m}{g}=32$ (equation-2) (divide with 'g' on both side)

We know,

The Constant of Proportionality equation is given;

$y=k\times x$ (equation-3)

Where 'k' is known as Constant of Proportionality.

Comparing equation-1 and equation-3;

$y=m$ and $x=g$

Now equation-2 become;

$k=\frac{y}{x}$

Plug $y=m$ and $x=g$ in above equation;

$\frac{m}{g}=k$ (equation-4)

By comparing equation-2 and equation-4;

$k=32$

So Constant of Proportionality is 32

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3 years ago

A rectangular hotel room is 3 meters by 5 meters. The owner of the hotel wants to re carpet the room with carpet that cost $15.0

eimsori [14]

Answer:

Step-by-step explanation:

The room is rectangular in shape. The formula for determining the area of a rectangle is expressed as

Area = length × width

The rectangular hotel room is 3 meters by 5 meters. The area of the room would be

Area = 3 × 5 = 15 square meters

The owner of the hotel wants to re carpet the room with carpet that cost $15.00 per square meter. This means that the cost to re carpet the room would be

15 × 15 = $225

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3 years ago

Which number line shows the solution to 5 + (−5)?

alex41 [277]

Answer:

first one is A and the second one is B.

Step-by-step explanation:

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Solve x2 + 8x = 33 by completing the square. Which is the solution set of the equation? {–11, 3} {–3, 11} {–4, 4} {–7, 7}

NemiM [27]

Answer:

The solution of the equation are 3 , -11

Step-by-step explanation:

* Lets revise how to make the completing square

- The form of the completing square is a(x - h)² + k, where a , h , k

are constant

- The general form of the quadratic is ax² + bx + c, where a , b , c

are constant

- To change the general form to the completing square form equate

them and find the constant a , h , k

* Now lets solve the problem

∵ x² + 8x = 33 ⇒ subtract 33 from both sides

∴ x² + 8x - 33 = 0

- lets change the general form to the completing square

∴ x² + 8x - 33 = a(x - h)² + k ⇒ solve the bracket of power 2

∴ x² + 8x - 33 = a(x² - 2hx + h²) + k ⇒ multiply the bracket by a

∴ x² + 8x - 33 = ax² - 2ahx + ah² + k ⇒ compare the two sides

∵ x² = ax² ⇒ ÷ x²

∴ a = 1

∴ -2ah = 8 ⇒ substitute the value of a

∴ -2(1)h = 8 ⇒ -2h = 8 ⇒ ÷ (-2)

∴ h = -4

∵ ah² + k = -33 ⇒ substitute the value of a and h

∴ (1)(-4)² + k = -33

∴ 16 + k = -33 ⇒ subtract 16 from both sides

∴ k = -49

∴ x² + 8x - 33 = (x + 4)² - 49

* Now lets solve the completing square

∵ (x + 4)² - 49 = 0 ⇒ add 49 to both sides

∴ (x + 4)² = 49 ⇒ take square root for both sides

∴ (x + 4) = ± 7

∵ x + 4 = 7 ⇒ subtract 4 from both sides

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∵ x + 4 = -7 ⇒ subtract 4 from both sides

∴ x = -11

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3 years ago

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