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3 years ago

MATH HELP ASAP! MARKING BRAINLIST!!!!!! maTH haLLP

Mathematics

2 answers:

AVprozaik [17]3 years ago

8 0

Answer:

75%?? im unsure

Step-by-step explanation:

alexgriva [62]3 years ago

4 0

It is a 75% increase

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The amount of chlorine in a swimming pool is proportional to the volume of water. The pool has 2.5 milligrams of chlorine per li

stira [4]

Answer:

There are <u>20,000 milligrams</u> chlorine in the pool.

Step-by-step explanation:

Given:

The chlorine per liter of water in the pool is 2.5 milligrams.

The volume of water in the swimming pool is 8000 gallons.

Now, to find the quantity of chlorine in the pool.

Let the quantity of chlorine be $x.$

The gallons of water in the swimming pool = 8000.

The milligrams of chlorine per liter of water in the pool = 2.5.

According to question, the amount of chlorine in the swimming pool is proportional to the volume of water.

So, 2.5 mg of chlorine is equivalent to 1 liter.

Thus, $x$ is equivalent to $8000.$

Now, to get the quantity of chlorine by using cross multiplication method:

$\frac{2.5}{1} =\frac{x}{8000}$

<em>By cross multiplying we get:</em>

$20000=x\\\\x=20,000\ mg.$

Therefore, there are 20,000 milligram chlorine in the pool.

6 0

3 years ago

Modern medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x

Anna11 [10]

Answer:

a) Figure attached

b) $y=1.31 x +98.57$

c) The correlation coefficient would be r =0.47719

d) $y=1.31 x +98.57=1.31*21 + 98.57 =126.08$

Step-by-step explanation:

(a) Draw a scatter diagram for the data.

See the figure attached

(b) Find x, y, b, and the equation of the least-squares line. (Round your answers to three decimal places.) x =__ y =__ b =__ y =__ + __x

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

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:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=6576-\frac{300^2}{14}=147.429$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=38186-\frac{300*1773}{14}=193.143$

And the slope would be:

$m=\frac{193.143}{147.429}=1.31$

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

$\bar x= \frac{\sum x_i}{n}=\frac{300}{14}=21.429$

$\bar y= \frac{\sum y_i}{n}=\frac{1773}{14}=126.643$

And we can find the intercept using this:

$b=\bar y -m \bar x=126.643-(1.31*21.429)=98.571$

So the line would be given by:

$y=1.31 x +98.57$

(c) Find the sample correlation coefficient r and the coefficient of determination r?2. (Round your answers to three decimal places.)

n=14 $\sum x = 300, \sum y = 1773, \sum xy=38186, \sum x^2 =6576, \sum y^2 =225649$

And in order to calculate the correlation coefficient we can use this formula:

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

$r=\frac{14(38186)-(300)(1773)}{\sqrt{[14(6576) -(300)^2][14(225649) -(1773)^2]}}=0.9534$

So then the correlation coefficient would be r =0.47719

What percentage of variation in y is explained by the least-squares model? (Round your answer to one decimal place.)

The % of variation is given by the determination coefficient given by $r^2$ and on this case $0.47719^2 =0.2277$ , so then the % of variation explaines is 22.8%.

(d) If a female baby weighs 21 pounds at 1 year, what do you predict she will weigh at 30 years of age? (Round your answer to two decimal places.) ___ lb

So we can replace in the linear model like this:

$y=1.31 x +98.57=1.31*21 + 98.57 =126.08$

7 0

3 years ago

Find the percentage based upon 400 people in the survey. 16%

MA_775_DIABLO [31]

To find a percentage, you the decimal point in the percent two places to the right 16% = 0.16. Then multiply.

0.16 • 400 = 64

16% of 400 = 64

3 0

3 years ago

Which of the following are identities? Check all that apply

Natasha2012 [34]

Answer:

A, C

Step-by-step explanation:

Actually, those questions require us to develop those equations to derive into trigonometrical equations so that we can unveil them or not. Doing it only two alternatives, the other ones will not result in Trigonometrical Identities.

Examining

A) True

$\frac{1-tan^{2}x}{2tanx} =\frac{1}{tan2x} \\ \frac{1-tan^{2}x}{2tanx} =\frac{1}{\frac{2tanx}{1-tan^{2}x}}\\ tan2x=\frac{1-tan^{2}x}{2tanx}$

Double angle $tan2\alpha =\frac{1 -tan^{2}\alpha }{2tan\alpha}$

B) False,

No further development towards a Trig Identity

C) True

Double Angle Sine Formula $sin2\alpha =2sin\alpha *cos\alpha$

$sin(8x)=2sin(4x)cos(4x)\\2sin(4x)cos(4x)=2sin(4x)cos(4x)$

D) False No further development towards a Trig Identity

$[sin(x)-cos(x)]^{2} =1+sin(2x)\\ sin^{2} (x)-2sin(x)cos(x)+cos^{2}x=1+2sinxcosx\\ \\sin^{2} (x)+cos^{2}x=1+4sin(x)cos(x)$

7 0

4 years ago

Read 2 more answers

Chelsea and her friends are making small fruit baskets for their neighbors. They have 90 pears, 45 peaches, and 75 apples. What

iVinArrow [24]

Answer:

15 baskets

Step-by-step explanation:

This question is a GCF question

The first step would be to find the factors of 45, 75 and 90

The factors of 45 are: 1, 3, 5, 9, 15, 45

The factors of 75 are: 1, 3, 5, 15, 25, 75

The factors of 90 are: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90

The greatest common factor is 15.

Therefore, the greatest number of baskets they can make if each basket has the same number of pears, the same number of peaches, and same number of apples, with no fruit leftover is 15 baskets

3 0

3 years ago