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3 years ago

Please help me!

Mathematics

2 answers:

soldi70 [24.7K]3 years ago

6 0

Answer:

-1.20

Step-by-step explanation:

You are correct because you just had to subtract 2.50 - 3.75 and you get -1.20.

kotegsom [21]3 years ago

6 0

Answer:

-1.25 feet below surface level.

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Which expressions are equivalent to 7•7•7•7•7?

mojhsa [17]

It's just AAAAA, no other answers. So just check A

8 0

3 years ago

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If Jenny can read 7 books in 8 days, exactly how many days would it take her to read 20 books?

muminat

Answer:

Step-by-step explanation:

Given,

No. of days taken by Jenny to read 7 books

= 8

So,

No. of days taken by her to read 1 book

$= \frac{8}{7}$

Therefore,

No. of days taken by her to read 20 books

$= \frac{8}{7} × 20$

[On Simplification]

$= \frac{160}{7}$

[On dividing]

= 22.85.....

[On approximating]

= 23 days (approx. )

Hence,

Jenny will take 23 days to read 20 books (Ans)

3 0

3 years ago

Read 2 more answers

How to solve -2p^2=16p+24

frozen [14]

Add 2p² to each side of the equation. Then you have

2p² + 16p + 24 = 0 .

Before you roll up your sleeves and start working on it, you can make it
even more convenient if you divide each side by 2 . Then you have:

p² + 8p + 12 = 0 .

Now you have a nice, comfortable, familiar-looking quadratic equation.
You can either factor the left side into (p + 6) (p + 2), or, if you can't find
the factors, you can apply the quadratic formula to it.

That's how to solve it, and find its two solutions.

8 0

3 years ago

Assume you have noted the following prices for books and the number of pages that each book contains. Book Pages (x) Price (y) A

belka [17]

Answer:

a) $y=0.00991 x +1.042$

b) $r^2 = 0.7503^2 = 0.563$

c) $r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

Step-by-step explanation:

Data given

x: 500, 700, 750, 590 , 540, 650, 480

y: 7.00, 7.50 , 9.00, 6.5, 7.50 , 7.0, 4.50

Part a

We want to create a linear model like this :

$y = mx +b$

Wehre

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

And:

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

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

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=2595100-\frac{4210^2}{7}=63085.714$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i){n}}=30095-\frac{4210*49}{7}=625$

And the slope would be:

$m=\frac{625}{63085.714}=0.00991$

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

$\bar x= \frac{\sum x_i}{n}=\frac{4210}{7}=601.429$

$\bar y= \frac{\sum y_i}{n}=\frac{49}{7}=7$

And we can find the intercept using this:

$b=\bar y -m \bar x=7-(0.00991*601.429)=1.042$

And the line would be:

$y=0.00991 x +1.042$

Part b

The correlation coefficient is given by:

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

For our case we have this:

n=7 $\sum x = 4210, \sum y = 49, \sum xy = 30095, \sum x^2 =2595100, \sum y^2 =354$

$r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

The determination coefficient is given by:

$r^2 = 0.7503^2 = 0.563$

Part c

$r=\frac{7(30095)-(4210)(49)}{\sqrt{[7(2595100) -(4210)^2][7(354) -(49)^2]}}=0.7503$

4 0

3 years ago

Question 5

Darina [25.2K]

Answer:

the answer is 12.24 .

Step-by-step explanation:

that answer is right is because when you add of those you get 530 , then you divide by how many numbers there are which is 7 , which equals to 75.7 . when you get that number ( 75.7) you subtract that number to 65,90,85,70,70,95, and 55 . when you get the total of all of those you add those . which is 10.7, 14.3 , 9.3 , 5.7 , 5.7 , 19.3 , and 20.7 . from adding those you get 85.7. you divide by 7 and get 12.24 . hope this helps :) .

8 0

2 years ago