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3 years ago

I will give brainliest if i can too

Mathematics

1 answer:

weeeeeb [17]3 years ago

6 0

Answer:

164 respondents answered "yes"

69 respondents answered "yes"

126 respondents answered "yes"

Step-by-step explanation:

Let's take these problems one at a time.

First problem: 195 Juniors and 215 Seniors. 2 out of 5 answered "yes".

Now let's first find the total number of students.

Total Students = 195 + 215

Total Students = 410

Now 2 out of 5 also means the 2/5 or 40% of the students answered yes.

To see how many said yes, we simple multiply the total number of students to the value of 40% or 0.40.

Total Students that answered "yes" = 410 x 0.40

Total Students that answered "yes" = 164

Second Problem: 125 Juniors and 220 Seniors. 0.80 answered "no".

Same process, we first look for the total number of students.

Total Students = 125 + 220

Total Students = 345

Now 0.80 or 80% of them said "no".

We take the total number of students and multiply the number of students to the value of 80% or 0.80.

Total Students that answered "no" = 345 x 0.80

Total Students that answered "no" = 276

Now to find out how many answered "yes", we subtract the total number of students to the students that said "no".

Total Students that answered "yes" = 345 - 276

Total Students that answered "yes" = 69

Third Problem 200 Juniors and 160 Seniors. 35% answered "yes"

Same process, we first look for the total number of students.

Total Students = 200 + 160

Total Students = 360

To see how many said yes, we simple multiply the total number of students to the value of 35% or 0.35.

Total Students that answered "yes" = 360 x 0.35

Total Students that answered "yes" = 126

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2 years ago

Suppose that from the past experience a professor knows that the test score of a student taking his final examination is a rando

DENIUS [597]

Answer:

$n=13.167^2 =173.369$ and if we round up to the nearest integer we got n =174

Step-by-step explanation:

Previous concepts

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Let X the random variable who represents the test score of a student taking his final examination. We know from the problem that the distribution for the random variable X is given by:

$X\sim N(\mu =73,\sigma =10.5)$

From the central limit theorem we know that the distribution for the sample mean $\bar X$ is given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

Solution to the problem

We want to find the value of n that satisfy this condition:

$P(71.5 < \bar X$

And we can use the z score formula given by:

$z=\frac{\bar X- \mu}{\frac{\sigma}{\sqrt{n}}}$

And we have this:

$P(\frac{71.5-73}{\frac{10.5}{\sqrt{n}}} < Z$

And we can express this like this:

$P(-0.14286 \sqrt{n} < Z< 0.14286 \sqrt{n} )=0.94$

And by properties of the normal distribution we can express this like this:

$P(-0.14286 \sqrt{n} < Z< 0.14286 \sqrt{n} )=1-2P(Z$

If we solve for $P(Z$ we got:

$P(Z$

Now we can find a quantile on the normal standard distribution that accumulates 0.03 of the area on the left tail and this value is: $z=-1.881$

And using this we have this equality:

$-1.881 = -0.14286 \sqrt{n}$

If we solve for $\sqrt{n}$ we got:

$\sqrt{n} = \frac{-1.881}{-0.14286}=13.167$

And then $n=13.167^2 =173.369$ and if we round up to the nearest integer we got n =174

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3 years ago

Alyssa drives 10 miles in 20 minutes. If she drove one hour in total at the same rate, how far did she go? i know the answer but

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Answer:

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Step-by-step explanation:

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2 years ago

The cost, c(x), for a taxi ride is given by c(x) = 2x + 2.00, where x is the number of minutes.

MArishka [77]

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3 years ago

1) 2 (x+3) +3 (5-x)=

Ugo [173]

Answer:

Below

Step-by-step explanation:

1. 2 (x+3) +3 (5-x)=

Simplifying

2(x + 3) + 3(5 + -1x) = 0

Reorder the terms:

2(3 + x) + 3(5 + -1x) = 0

(3 * 2 + x * 2) + 3(5 + -1x) = 0

(6 + 2x) + 3(5 + -1x) = 0

6 + 2x + (5 * 3 + -1x * 3) = 0

6 + 2x + (15 + -3x) = 0

Reorder the terms:

6 + 15 + 2x + -3x = 0

Combine like terms: 6 + 15 = 21

21 + 2x + -3x = 0

Combine like terms: 2x + -3x = -1x

21 + -1x = 0

Solving

21 + -1x = 0

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-21' to each side of the equation.

21 + -21 + -1x = 0 + -21

Combine like terms: 21 + -21 = 0

0 + -1x = 0 + -21

-1x = 0 + -21

Combine like terms: 0 + -21 = -21

-1x = -21

Divide each side by '-1'.

x = 21

Simplifying

x = 21

2. 3 (y+2) -4y=-24y

Simplifying

3(y + 2) + -4y = -24y

Reorder the terms:

3(2 + y) + -4y = -24y

(2 * 3 + y * 3) + -4y = -24y

(6 + 3y) + -4y = -24y

Combine like terms: 3y + -4y = -1y

6 + -1y = -24y

Solving

6 + -1y = -24y

Solving for variable 'y'.

Move all terms containing y to the left, all other terms to the right.

Add '24y' to each side of the equation.

6 + -1y + 24y = -24y + 24y

Combine like terms: -1y + 24y = 23y

6 + 23y = -24y + 24y

Combine like terms: -24y + 24y = 0

6 + 23y = 0

Add '-6' to each side of the equation.

6 + -6 + 23y = 0 + -6

Combine like terms: 6 + -6 = 0

0 + 23y = 0 + -6

23y = 0 + -6

Combine like terms: 0 + -6 = -6

23y = -6

Divide each side by '23'.

y = -0.2608695652

Simplifying

y = -0.2608695652

3. -(x+2) -2(1-x)=

Simplifying

-1(x + 2) + -2(1 + -1x) = 0

Reorder the terms:

-1(2 + x) + -2(1 + -1x) = 0

(2 * -1 + x * -1) + -2(1 + -1x) = 0

(-2 + -1x) + -2(1 + -1x) = 0

-2 + -1x + (1 * -2 + -1x * -2) = 0

-2 + -1x + (-2 + 2x) = 0

Reorder the terms:

-2 + -2 + -1x + 2x = 0

Combine like terms: -2 + -2 = -4

-4 + -1x + 2x = 0

Combine like terms: -1x + 2x = 1x

-4 + 1x = 0

Solving

-4 + 1x = 0

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '4' to each side of the equation.

-4 + 4 + 1x = 0 + 4

Combine like terms: -4 + 4 = 0

0 + 1x = 0 + 4

1x = 0 + 4

Combine like terms: 0 + 4 = 4

1x = 4

Divide each side by '1'.

x = 4

Simplifying

x = 4

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6 0

3 years ago