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3 years ago

If someone drove 640 miles in 4 hours how would you determine they would travel in 12?

Mathematics

1 answer:

NISA [10]3 years ago

3 0

Answer:

Step-by-step explanation:

if someone drove 640 miles in 4 hours,

, it means that they drove 640/4=160 miles per hour

in 12 hours

160*12=1920

640............................4 h

640*3.........................4*3 hours

which give syou the same answer

1920.............................12 hours

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Answer:

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Step-by-step explanation:

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3 years ago

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Answer:

Step-by-step explanation:

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David reads this advert on his country council website 70% of the area of woodland in the country is native woodland this means

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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

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

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3 years ago

13.

Artist 52 [7]

Answer:

5 units

Step-by-step explanation:

An isosceles triangle is a triangle with two legs that have the same length. The perimeter of a triangle is the sum of the lengths of all sides of the triangle. Now taking this into account, we know that:

2L + B = 14 units

Where:

L is the measure of one leg

B is the measure of the base

Since two legs are the same and the base is 1 less, this means the measure of each leg would be:

B = L -1

Now we have two equations:

2L + B = 14 units

B = L- 1

We plug one equation into the other and make 1 equation:

2L + (L-1) = 14 units

Get rid of the parentheses:

2L + L - 1 = 14

Combine like terms:

3L - 1 = 14

Add 1 to both sides of the equation:

3L - 1 + 1 = 14 + 1

3L = 15

Divide both sides by 3:

3L/3 = 15/3

L = 5

So the length of a leg is 5 units

Let's check!

B = L - 1

B = 5 - 1

B = 4

Then we use that to solve for the perimeter:

2L + B

2(5) + 4

10 + 4 = 14

7 0

3 years ago