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2 years ago

Millie has a box of 1 hundred cubes. She also has a bag of 70 cubes. How many trains of 10 cubes can she make?

Mathematics

2 answers:

Degger [83]2 years ago

6 0

You can make 10 rows with 100 cubes, and you can also make 7 rows with 70 cubes, 10+7=17, the answer is 17.

Serga [27]2 years ago

5 0

100 + 70 = 170

170 / 10 = 17

17, 10 cube trains

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Pablo and Nadia are playing a game on a coordinate grid. Pablo puts a playing piece at point (-2, 3) and Nadia puts a playing pi

7nadin3 [17]

Answer:

The distance between the two playing pieces is of 6.4 units.

Step-by-step explanation:

Suppose we have two points:

$A = (x_{1}, y_{1})$

$B = (x_{2}, y_{2})$

The distance between these points is:

$D = \sqrt{(x_{2} - x_{1})^{2} + (y_{2} - y_{1})^{2}}$

Distance between:

A(-2,3) and B(3,-1)

$D = \sqrt{(3 - (-2))^{2} + (-1 - 3)^{2}} = \sqrt{41} = 6.4$

The distance between the two playing pieces is of 6.4 units.

5 0

2 years ago

An online article about an opinion poll says that "41% of Americans own a gun." The poll is based on online survey interviews wi

sergejj [24]

Answer:

See below

Step-by-step explanation:

A) The population of the poll is the United States Population EXCLUDING New England States. In other words, the population is all USA population except the New England population. Remember that population is all the set of individuals from where you extract your sample. The sample are those 2,700 adults interviewed.

B) The sampling used is, as said in the statement, a randome sampling.

C) Yes! There could be a bias because of the exclusion of New England States if the people who lives there tends to have more guns than the average american population. This could be, for example, due to that those states have the least gun owning in America or, contrary, if they have the highest. If Rode Island is the most violent state and has the highest gun owning rate, the results could be biased. However, we can't confirm it without seeing the data, but there is possible.

3 0

2 years ago

G find the area of the surface over the given region. use a computer algebra system to verify your results. the sphere r(u,v) =

Svetach [21]

Presumably you should be doing this using calculus methods, namely computing the surface integral along $\mathbf r(u,v)$ .

But since $\mathbf r(u,v)$ describes a sphere, we can simply recall that the surface area of a sphere of radius $a$ is $4\pi a^2$ .

In calculus terms, we would first find an expression for the surface element, which is given by

$\displaystyle\iint_S\mathrm dS=\iint_S\left\|\frac{\partial\mathbf r}{\partial u}\times\frac{\partial\mathbf r}{\partial v}\right\|\,\mathrm du\,\mathrm dv$

$\dfrac{\partial\mathbf r}{\partial u}=a\cos u\cos v\,\mathbf i+a\cos u\sin v\,\mathbf j-a\sin u\,\mathbf k$
$\dfrac{\partial\mathbf r}{\partial v}=-a\sin u\sin v\,\mathbf i+a\sin u\cos v\,\mathbf j$
$\implies\dfrac{\partial\mathbf r}{\partial u}\times\dfrac{\partial\mathbf r}{\partial v}=a^2\sin^2u\cos v\,\mathbf i+a^2\sin^2u\sin v\,\mathbf j+a^2\sin u\cos u\,\mathbf k$
$\implies\left\|\dfrac{\partial\mathbf r}{\partial u}\times\dfrac{\partial\mathbf r}{\partial v}\right\|=a^2\sin u$

So the area of the surface is

$\displaystyle\iint_S\mathrm dS=\int_{u=0}^{u=\pi}\int_{v=0}^{v=2\pi}a^2\sin u\,\mathrm dv\,\mathrm du=2\pi a^2\int_{u=0}^{u=\pi}\sin u$
$=-2\pi a^2(\cos\pi-\cos 0)$
$=-2\pi a^2(-1-1)$
$=4\pi a^2$

as expected.

6 0

2 years ago

Suppose that we want to investigate whether curfews correlate with differences in grades for students in middle school. We selec

Anton [14]

Answer:

Step-by-step explanation:

Hello!

Given the variables

X: Curfew of middle school students (Categorized Yes/No)

Y: Average grade of middle school students. (Categorized: A, B, C, and D)

The objective is to test if there is an association between both variables, you have to conduct a Chi-Square test of independence.

In the null hypothesis, you state that both variables are independent vs. the alternative hypothesis that the variables are dependent.

The hypotheses for this test are:

H₀: Pij= Pi. * P.j i= (1)Yes, (2)No; j= (1)A, (2)B, (3)C, (4)D

H₁: Te variables are not independent.

α: 0.05

$X^2= sum\frac{(O_{ij}-E_{ij})^2}{E_{ij}} ~~X_{(r-1)*(c-1)}$

Where

Oij is the observed frequency for the i-row and j-column

Eij is the expected frequency for the i-row and j-column

r= number of categories in the rows

c= number of categories in the columns

$X^2_{H_0}= 1.4796703$

p-value: 0.687

The p-value is greater than the significance level, so the decision is to not reject the null hypothesis. So using a 5% significance level, you can conclude that having a curfew and the average grades of middle schoolers are two independent variables.