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1 year ago

11

Kathy earned $300 mowing lawns last summer. She spent all her earnings on a new CD player and new CDs. If Kathy paid $90 for the

CD player what percent of her summer earnings did she spend on the CDs?

1 answer:

Leona [35]1 year ago

7 0

Answer:

The answer is 30% percent.

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A spinner has 10 equal-sized sections. To win the game, the pointer must land on a blue section

GrogVix [38]

Answer:

1/10

Step-by-step explanation:

Given data

Total number of possible outcomes /sample space S= 10

In this problem we are required to solve for the probability of obtaining the favourable outcome which is obtaining a blue

Hence the probability of obtaining a blue is

Pr(blue) = 1/10

8 0

2 years ago

a car can travel 19.6 miles for every 1 gallon of gasoline. calculate the number of miles the car can travel on 13.8 gallons of

lord [1]

I believe it 270.48 miles.

6 0

2 years ago

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

2 years ago

X squared -8x+14=2x-7

Stella [2.4K]

Answer:

x = 3 or x = 7

Step-by-step explanation:

X² - 8x + 14 = 2x - 7

x² - 8x + 14 - 2x + 7 = 0

Now we have a quadratic equation ;

x² - 10x + 21 = 0

-3 and - 7 gives a sum of - 10 and a product of 21

x² - 3x - 7x + 21 = 0

x(x - 3) - 7(x - 3) = 0

(x - 3) = 0 or (x - 7) = 0

x = 3 or x = 7

5 0

2 years ago

HALP me please, mathematics

malfutka [58]

X=7 (let me know if you would like to know how I got the answer)

3 0

3 years ago