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3 years ago

Wanda spent 4 1/8 hours studying last night. She spent 1/3 of the time studying math. How much time did she spend studying math?

Mathematics

1 answer:

julia-pushkina [17]3 years ago

4 0

Answer:

$1\frac{3}{8}$ hours, or 1 hour and 22.5 minutes

Step-by-step explanation:

Wanda spends a third of her $4\frac{1}{8}$ hours studying math. Let us multiply these two fractions to find how much time she spent. Our first step would be to convert the mixed number into an improper fraction, as mixed numbers are hard to manipulate with:

$4\frac{1}{8} =\\\frac{33}{8}$

Now let us multiply:

$\frac{1}{3} *\frac{33}{8} =\\\frac{11}{8}$

If we wish, we can convert this into a mixed number:

$\frac{11}{8}= \\1\frac{3}{8}$

or, 1 hour and 22.5 minutes.

Therefore, Wanda spent $1\frac{3}{8}$ hours, or 1 hour and 22.5 minutes studying math.

I hope this helps! Let me know if you have any questions :)

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Find domain and range -√x-5+10

inysia [295]

When finding the domain of a square root, you have to know that it is impossible to get the square root of 0 or any negative number. since domain is possible x values this means that x cannot be 0 or any number less than 0. However, you can find the square root of the smallest most infinitely small number greater than 0. since an infinitely small number close to zero can not be written out, we must must say that the domain starts at 0 exclusive. exclusive is represented by an open or close parenthesis so in this case the domain starts with:
(0,
we can get the square root of any number larger than 0 up to infinity but infinity can never be reached so it is also exclusive. So so the ending of our domain would be:
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So the answer if the square root is only over the x the answer is
(0, infinity)

But if the square root is over the x- 5 then this would brIng a smaller amount of possible x values. since anything under the square root sign has to be greater than 0, you can say that:
(x - 5) > 0
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3 years ago

20,10,5, ... Find the 9th term.

iren [92.7K]

Answer:

0.078125.

Step-by-step explanation:

This is a geometric sequence with first term a1 = 20 and common ratio r = 10/20 = 5/10 = 0.5.

nth term = a1 r^(n -1) so here:

9th term = 20(0.5)^(9-1)

= 20(0.5)^8

= 0.078125.

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2 years ago

At a recent county fair, you observed that at one stand people's weight was forecasted, and were surprised by the accuracy (with

MatroZZZ [7]

Answer:

a)Slope: $\hat \beta_1 =\frac{7625.9}{1248.9}=6.106$

Intercept: $\hat \beta_o = 157.955 -6.106 (69.686)=-267.548$

b) $r=\frac{7625.9}{\sqrt{[1248.9][94228.8]}}=0.657$

And the determination coeffecient is $r^2 = 0.657^2 =0.432$

Step-by-step explanation:

Data given and definitions

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

The sum of squares "is the sum of the square of variation, where variation is defined as the spread between each individual value and the grand mean"

When we conduct a multiple regression we want to know about the relationship between several independent or predictor variables and a dependent or criterion variable.

n=110, $\sum x_i y_i = \sum (X-\bar X)(Y-\bar Y) =7625.9,\sum x^2_i=\sum (x-\bar x)^2 =1248.9 , sum y^2_i=\sum(y-\bar y)^2 =94228.8$

$\sum Y_i =17375 , \sum X_i = 7665.5$

Part a

The slope is given by this formula:

$\hat \beta_1 =\frac{\sum (x-\bar x) (y-\bar y)}{\sum (x-\bar x )^2}$

If we replace we got:

$\hat \beta_1 =\frac{7625.9}{1248.9}=6.106$

We can find the intercept with the following formula

$\hat \beta_o = \bar y -\hat \beta_1 \bar x$

We can find the average for x and y like this:

$\bar X=7665.5/110 =69.686, \bar y= 17375/110=157.955$

And replacing we got:

$\hat \beta_o = 157.955 -6.106 (69.686)=-267.548$

Part b

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

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

For our case we have this:

n=110, $\sum x_i y_i = \sum (X-\bar X)(Y-\bar Y) =7625.9,\sum x^2_i=\sum (x-\bar x)^2 =1248.9 , sum y^2_i=\sum(y-\bar y)^2 =94228.8$

So we can find the correlation coefficient replacing like this:

$r=\frac{7625.9}{\sqrt{[1248.9][94228.8]}}=0.657$

And the determination coeffecient is $r^2 = 0.657^2 =0.432$

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k + 20 = 3k - 120
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ipn [44]

-3/2

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3 years ago