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3 years ago

I need help with this simple question, I am really dumb haha

Mathematics

2 answers:

JulijaS [17]3 years ago

5 0

So, to find the day rate, we divide 90 by 6 = 15
So then we find 15n = 300 for the rate.
n = 20
It will take Stephen 20 days to read a 300-page book

kifflom [539]3 years ago

3 0

Answer:

n = 20```````````````````````````````````````````````

Step-by-step explanation:

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Arrange the quantities in order from smallest to largest. 2.6 km, 109,000 mm, 41.7 hm

Aleksandr-060686 [28]

The order of the values using the basic unit of meters from smallest to largest. is: 109000 mm < 2.6 km < 41.7 hm

What are the units of measurement of distance or length?

Distance is the gap between any two points under consideration.

The basic unit for measuring distance is the meter.

There are larger as well as smaller units for measuring length or distance which are based on the unit of meter.

The units are as follows:

millimeter, mm = 0.001 m

centimeter, cm = 0.01 m

decimeters, dm = 0.1 m

meter, m = 1 m

kilometer, km = 1000 m

hectometer, hm = 100 m

Now to compare the given quantities making the units same as two quantities can only be compared only when there units are same :

Considering the given values;

2.6 km = 2600 m

109,000 mm = 109 m

41.7 hm = 4170 m

Therefore, after comparison arranging the quantities in order from smallest to largest is 109000 mm < 2.6 km < 41.7 hm

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4 0

8 months ago

What is the slope of the line that contains points (3,-9) and (-2,16) please help !!

Furkat [3]

Slope = Change in Y / change in x

Slope = (16 - -9) / (-2 - 3)

Slope = 25/-5

Slope = -5

7 0

3 years ago

An experiment was conducted to observe the effect of an increase in temperature on the potency of an antibiotic. Three 1-ounce p

ludmilkaskok [199]

Answer:

a) $y=-0.317 x +46.02$

b) Figure attached

c) $S^2=\hat \sigma^2=MSE=\frac{190.33}{10}=19.03$

Step-by-step explanation:

We assume that th data is this one:

x: 30, 30, 30, 50, 50, 50, 70,70, 70,90,90,90

y: 38, 43, 29, 32, 26, 33, 19, 27, 23, 14, 19, 21.

a) Find the least-squares line appropriate for this data.

For this case we need to calculate the slope with the following formula:

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

Where:

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

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

So we can find the sums like this:

$\sum_{i=1}^n x_i = 30+30+30+50+50+50+70+70+70+90+90+90=720$

$\sum_{i=1}^n y_i =38+43+29+32+26+33+19+27+23+14+19+21=324$

$\sum_{i=1}^n x^2_i =30^2+30^2+30^2+50^2+50^2+50^2+70^2+70^2+70^2+90^2+90^2+90^2=49200$

$\sum_{i=1}^n y^2_i =38^2+43^2+29^2+32^2+26^2+33^2+19^2+27^2+23^2+14^2+19^2+21^2=9540$

$\sum_{i=1}^n x_i y_i =30*38+30*43+30*29+50*32+50*26+50*33+70*19+70*27+70*23+90*14+90*19+90*21=17540$

With these we can find the sums:

$S_{xx}=\sum_{i=1}^n x^2_i -\frac{(\sum_{i=1}^n x_i)^2}{n}=49200-\frac{720^2}{12}=6000$

$S_{xy}=\sum_{i=1}^n x_i y_i -\frac{(\sum_{i=1}^n x_i)(\sum_{i=1}^n y_i)}=17540-\frac{720*324}{12}{12}=-1900$

And the slope would be:

$m=-\frac{1900}{6000}=-0.317$

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

$\bar x= \frac{\sum x_i}{n}=\frac{720}{12}=60$

$\bar y= \frac{\sum y_i}{n}=\frac{324}{12}=27$

And we can find the intercept using this:

$b=\bar y -m \bar x=27-(-0.317*60)=46.02$

So the line would be given by:

$y=-0.317 x +46.02$

b) Plot the points and graph the line as a check on your calculations.

For this case we can use excel and we got the figure attached as the result.

c) Calculate S^2

In oder to calculate S^2 we need to calculate the MSE, or the mean square error. And is given by this formula:

$MSE=\frac{SSE}{df_{E}}$

The degred of freedom for the error are given by:

$df_{E}=n-2=12-2=10$

We can calculate:

$S_{y}=\sum_{i=1}^n y^2_i -\frac{(\sum_{i=1}^n y_i)^2}{n}=9540-\frac{324^2}{12}=792$

And now we can calculate the sum of squares for the regression given by:

$SSR=\frac{S^2_{xy}}{S_{xx}}=\frac{(-1900)^2}{6000}=601.67$

We have that SST= SSR+SSE, and then SSE=SST-SSR= 792-601.67=190.33[/tex]

So then :

$S^2=\hat \sigma^2=MSE=\frac{190.33}{10}=19.03$

5 0

2 years ago

Find the Inverse y = x+10/7

Alona [7]

Answer:

x - $\frac{10}{7}$

Step-by-step explanation:

y = x + 10/7

x = y + 10/7

x - 10/7 = y

y = x - 10/7

x - $\frac{10}{7}$

3 0

3 years ago

A family has two cars. The first car has a fuel efficiency of 15 miles per gallon of gas and the second has a fuel efficiency of

professor190 [17]

The fuel consumption of each of the cars during the week are as follows;

The first car consumes 20 gallons of fuel.

The second car consumes 30 gallons of fuel.

Reasons:

Fuel efficiency of the first car = 15 miles per gallon

Fuel efficiency of the second car = 35 miles per gallon

Combined distance traveled by the two cars in a week = 1,350 miles

The total gas consumption during the week = 50 gallons

Let x represent the number of gallons consumed by the first car, and let y

represent the number of gallons consumed by the second car, we get the

following system of simultaneous equations;

15·x + 35·y = 1,350...(1)

x + y = 50...(2)

Therefore;

y = 50 - x

Which gives;

15·x + 35 × (50 - x) = 1,350

15·x + 1,750 - 35·x = 1,350

1,750 - 1,350 = 35·x - 15·x = 20·x

400 = 20·x

x = 400 ÷ 20 = 20

The number of gallons consumed by the first car, x = 20 gallons

From equation (2), we have;

x + y = 50

y = 50 - x

Therefore;

y = 50 - 20 = 30

The number of gallons consumed by the second car, y = 30 gallons

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6 0

1 year ago