28 students in the class took an algebra test. If 12 students pass the test what percent failed

Answer:

The volume of the first acid solution (containing 20% acid) in the mixture is 14 liters

The volume of the second acid solution (containing 40% acid) in the mixture is 14 liters

The volume of the third acid solution (containing 70% acid) in the mixture is 28 liters

Step-by-step explanation:

The percentage of acid in the first acid solution = 20%

The percentage of acid in the second acid solution = 40%

The percentage of acid in the third acid solution = 70%

The volume they want to use the three solutions to obtain a mixture of = 56 liters

The concentration of the mixture they want to obtain = 50%

The amount of the 70% solution to be used = 2 × The volume of the 40% solution to be included

Let 'x', 'y', and 'z', represent the volumes of the first second and third acid solutions in the mixture

Therefore, from the question parameters, we get;

x + y + z = 56...(1)

z = 2·y...(2)

0.2·x + 0.4·y + 0.7·z = 0.5 × 56...(3)

Multiplying equation (3) by 10 and then subtracting equation (1) multiplied by 2 from the result gives;

10 × (0.2·x + 0.4·y + 0.7·z = 0.5 × 56) = 2·x + 4·y + 7·z = 5 × 56 = 280

2·x - 2·x + 4·y - 2·y + 7·z - 2·y = 280 - 2 × 56 = 168

2·y + 5·z = 168

From equation (2) and (4), we get;

2·y + 5·z = 2·y + 5×(2·y) = 168

12·y = 168

y = 168/12 = 14

The volume of the second acid solution in the mixture, y = 14 liters

From equation (2), we have;

z = 2·y

∴ z = 2 × 14 = 28

The volume of the third acid solution in the mixture, z = 28 liters

From equation (1), we get;

x + y + z = 56

x = 56 - (y + z)

∴ x = 56 - (14 + 28) = 14

The volume of the first acid solution in the mixture, x = 14 liters.

The time it takes for a sunflower seed to hit the ground is approximately 3.1 seconds.

To solve this problem, we need to find how long it takes the distance function to reach a value of 150 feet (the height of the balcony). When the sunflower seed falls to the ground, the distance to the balcony is zero.

The expression can be set like this:

\(d(t) = 16t^2 = 150\)

Solving for t gives:

\(t^2 = 150/16\)

t = sqrt(9.375) seconds

therefore, Rounded to the nearest tenth of a second the time it takes for a sunflower seed to hit the ground is approximately 3.1 seconds.

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To find the average value of x^2 in the one-dimensional infinite potential energy well, we need to use the wave function for the particle in the well, which is given by:

ψn(x) = sqrt(2/L) * sin(nπx/L)

where n is a positive integer and L is the width of the well.

The probability density of finding the particle at a position x is given by:

|ψn(x)|^2 = (2/L) * sin^2(nπx/L)

Using this probability density, we can find the average value of x^2 by integrating x^2 multiplied by the probability density over the entire well:

= ∫(x^2)(2/L) * sin^2(nπx/L) dx from 0 to L

Using the trigonometric identity sin^2θ = (1/2) - (1/2)cos(2θ), we can simplify the integral as follows:

= (1/L) * ∫(x^2) dx from 0 to L - (1/L) * ∫(x^2)cos(2nπx/L) dx from 0 to L

The first integral is simply the average value of x^2 over the entire well, which is L^2/3. The second integral can be evaluated using integration by parts, resulting in:

(1/L) * ∫(x^2)cos(2nπx/L) dx = (L^2/2nπ)^2 * [sin(2nπx/L) - (2nπx/L)cos(2nπx/L)] from 0 to L

Plugging this into our original equation, we get:

= L^2/3 - (L^2/2nπ)^2 * [sin(2nπ) - 2nπcos(2nπ)] + (L^2/2nπ)^2 * [sin(0) - 0]

Since sin(0) = 0 and sin(2nπ) = 0, the equation simplifies to:

= L^2/3 - (L^2/2nπ)^2 * (-2nπ) = L^2/3 + (L^2/2) * n^2π^2

Finally, we can substitute L^2/4π^2 for 1/2 in the expression above to get:

= L^2/3 + L^2/4 * n^2π^2 - L^2/4π^2 * n^2π^2

Simplifying further, we get:

= L^2/3 - L^2/4π^2 * n^2π^2

which is the desired result.
To show that the average value of x^2 in a one-dimensional infinite potential energy well is L^2(1/3 - 1/2n^2 π^2), we need to follow these steps:

Step 1: Define the wave function.
For an infinite potential energy well of width L, the wave function Ψ_n(x) is given by:
Ψ_n(x) = √(2/L) sin(nπx/L)

Step 2: Compute the probability density function.
The probability density function, ρ(x), is given by the square of the wave function, |Ψ_n(x)|^2:
ρ(x) = (2/L) sin^2(nπx/L)

Step 3: Calculate the expectation value of x^2.
The expectation value (average value) of x^2, denoted as , is given by the integral of the product of x^2 and the probability density function over the width of the well (0 to L):
= ∫[x^2 ρ(x)] dx from 0 to L

Step 4: Perform the integral.
= ∫[x^2 (2/L) sin^2(nπx/L)] dx from 0 to L

After solving this integral, you will find that:

= L^2(1/3 - 1/2n^2 π^2)

This confirms that the average value of x^2 in the one-dimensional infinite potential energy well is indeed L^2(1/3 - 1/2n^2 π^2).

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Answer:

x = 13  and  x = -3

Step-by-step explanation:

divide each side by 2 first and get:

(x-5)² = 64

take the square root of each side next and get:

x - 5 = \(\sqrt{64}\)

x - 5 = 8  and  x - 5 = -8

x = 13  and  x = -3

Answer:

x = 13 and x = -13

Step-by-step explanation:

.........

Answer:

slope of CE is 2/3

Step-by-step explanation:

used the slope formula: change in y-values / change in x-values

Answer:

Step-by-step explanation:

9514 1404 393

Answer:

  4

Step-by-step explanation:

The greatest common factor of 28 and 68 is 4.

  28 = 4×7

  68 = 4×17

Each person could have received 4 baseball cards.

Answer: A because 9 is bigger than 2 so it stay as a 9 making the anwer 41.9.

Answer:

The answer would be A.

Step-by-step explanation:

To be rounded to 41.9, the digit in the 100ths place would have to be less than 4. Using process of elimination we can see that the only answer left is A (41.924). I hope that this helps! :)

Answer:

-3

Step-by-step explanation:

hope this helps

ANSWER

Its -3

EXPLANATION STEP BY STEP

1/-3=-3/1

=-3

Answer:

B

Step-by-step explanation:

Please put me as the brainliest :)

Answer:

Markdown

Step-by-step explanation:

For example: the price of the shirt was $10.00 It had a markdown of 15%. This would be $8.5.

Answer:

the fourth anwser

markdown

Answer:

Step-by-step explanation:

Given;

Principal = $15,650

Rate = 8.5%

Time = 36months = 3years

Substitute and get the interest;

Simple interest = 15,650 * 8.5 * 3/100

Simple interest  = 399075/100

Simple interest  = $3990.75

Amount = Principal + Interest

Amount = $15,650 + $ $3990.75

The total amount she will pay by the end of the loan = $19,640.75

In total, Menaha traveled 97km 1000m (97.1km).

Distance is a numerical measurement of how far apart two objects, points, or places are in space. Distance can be measured in linear units such as meters, kilometers, feet, miles, etc. It can also be measured in angular units such as degrees or radians.

Distance can also refer to the space between two points in time, such as the time between two events. Distance can be used to measure physical distance, time, or even emotional distance.
To calculate this, the two distances must be added together.
The train distance is =86km 520m (86.52km)

and the car distance is =11km 480m (11.48km).
When added together, =86km 520m+11km 480m = 97.52km.
However, since the distances are measured in km and m,
it is necessary to convert the measurements into a single unit of measurement.
To do this, the measurements must be converted into metres.
The train distance is 86,520 metres

And the car distance is 11,480 metres.
When added together,

the total distance is 97,000 metres (97km).

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Answer:

y = -1x + 5

Step-by-step explanation:

y = mx + c

y = gradient(x intercept) + y intercept

y = -1x + 5

Answer:

24

Step-by-step explanation:

8 / 1/3

8 x 3 = 24

Answer:

CPCTC

Step-by-step explanation:

If two triangles are similar, we can prove by CPCTC

r/s ×3

calculate the product

r×3/s

use the commutative property to reorder the terms

Answer : 3r/s

PLEASE MARK ME AS BRAINLIEST

Answer:

hi I did not fully understand, so I did it on the calculator

Performing a Chi-Square test is a statistical tool used to determine if there is a significant difference between observed and expected data. The test helps to analyze categorical data by comparing observed frequencies to the expected frequencies. The p-value in a Chi-Square test refers to the probability of obtaining the observed results by chance alone.

If a p-value lower than 0.01 is obtained in a Chi-Square test, it means that the results are statistically significant. In other words, there is strong evidence to reject the null hypothesis, which states that there is no significant difference between the observed and expected data. This means that the observed data is not due to chance alone, but rather to some other factor or factors.

The mean, or average, is not directly related to the Chi-Square test or the p-value. The Chi-Square test is specifically used to determine the significance of the observed data. However, the mean can be used as a measure of central tendency for continuous data, but it is not applicable to categorical data.

In conclusion, obtaining a p-value lower than 0.01 in a Chi-Square test means that there is strong evidence to reject the null hypothesis, and that the observed data is statistically significant.

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These special prime pairs are best known as "twin primes."

The question is about the unproven conjecture that there exist infinitely many pairs of prime numbers that differ by two, which are best known as a specific term. These special prime numbers, such as (17 and 19) or (1019 and 1021), are sometimes called "prime pairs" but they are best known as "twin primes."

Twin primes are the pairs of prime numbers that differ by a number of two, such as (3, 5), (5, 7), (11, 13), (17, 19), and so on. The conjecture that there are infinitely many twin primes is one of the oldest unsolved problems in number theory.

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The number of blocks with exactly one red face is 25000 - 1200 = 23800.

The entire 10 * 10 * 10 cube has a total of 6 x 10^2 = 600 red faces, since all six faces are painted red.

When the cube is cut into ten 10 * 10 * 1 slices, each slice will have 100 red faces (since it has 10 * 10 = 100 square faces in total). Thus, all ten slices will have a combined total of 1000 red faces.

When each of these ten slices is cut into twenty-five 2 * 2 * 1 blocks, each block will have at least one face that was originally a red face. Specifically, there are two 2 * 2 faces and two 1 * 2 faces on each block, so at least one of these must be a red face. Therefore, there are a total of 25 x 1000 = 25000 blocks that have at least one red face.

To count the number of blocks with exactly one red face, we need to subtract the number of blocks with more than one red face from the total number of blocks with at least one red face.

Each 2 * 2 * 1 block has four edges, and each edge is shared by two adjacent blocks. Therefore, the total number of edges in the 25000 blocks is 4 x 25000 / 2 = 50000.

However, each block with more than one red face contributes twice to this count, since it shares two red edges with its neighbors. There are 600 blocks with more than one red face (the ones in the center of each slice), so they contribute 2 x 600 = 1200 to the total count.

Thus, the number of blocks with exactly one red face is 25000 - 1200 = 23800.

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The simplification form of the provided expression is x¹⁸a³b³ option

(d) x¹⁸a³b³ is correct.

In mathematics, integer exponents are exponents that should be integers. It may be a positive or negative number. In this situation, the positive integer exponents determine the number of times the base number should be multiplied by itself.

It is given that:

The expression:

\(= \rm (\dfrac{x^4a^2b^3}{x^{-2}ab^2})^3\)

After using the integer exponent property:

\(\rm =\dfrac{x^{12}a^6b^9x^6}{a^3b^6}\)

= a³b³x¹⁸ Or

=x¹⁸a³b³

Thus, the simplification form of the provided expression is x¹⁸a³b³ option

(d) x¹⁸a³b³ is correct.

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Answer:

The answer is A

Step-by-step explanation:

The race is approximately 1/2 a mile long and and that they all ran the same distance if the race is 1/2 mile long then they couldn't have ran more then that

Answer:

A

Step-by-step explanation:

they all ran the 1/2 mile

Simplifying the expression, -(4x³+x²) + 2(x³ - 3x²), the simplest form would be: B. -2x³ - 7x².

To simplify the expression, -(4x³+x²) + 2(x³ - 3x²), do the following:

Apply the distributive property to eliminate the parentheses

-4x³ - x² + 2x³ - 6x²

Combine like terms together

-4x³ + 2x³ - 6x² - x²

-2x³ - 7x²

Thus, simplifying the expression, -(4x³+x²) + 2(x³ - 3x²), the simplest form would be: B. -2x³ - 7x².

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1/7 of the animals in the zoo are male monkeys.

To find the fraction of animals in the zoo that are male monkeys, we have to calculate the product of the fractions representing the proportion of monkeys and the proportion of male monkeys among them.

Given that 1/5 of the animals in the zoo are monkeys, we will then represent this as:

= 1/5

= 5/25.

And 5/7 of the monkeys are male which is written as 5/7.

To get fraction of male monkeys, we will multiply these two fractions:

= (5/25) * (5/7)

= 25/175

= 1/7.

Full question:

1/5 of the animals in the zoo are monkeys 5/7 of the monkeys are male. What fraction of the animals in the zoo are male monkeys?

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Answer:

7 :))

Step-by-step explanation:

According to the given percentages, 18% of the students at the orientation are male arts majors.

The statement correctly calculates that 60% of the students at the orientation are men and 30% are arts majors.

To determine the percentage of students who are male arts majors, we multiply these two percentages together: 60% x 30% = 18%. Therefore, 18% of the students at the orientation are male arts majors.

This calculation follows the principles of probability, where the intersection of two events (being a male and being an arts major) is determined by multiplying the probabilities of each event occurring individually.

In this case, it results in 18% of the students meeting both criteria.


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Question - Sixty percent of the students at an orientation are men and 30% of the students at the orientation are arts majors. Therefore, 60% X 30% = 18% of the students at the orientation are male arts majors.

A parent function is the simplest function of a family of functions which preserves the shape of all other functions in that family.

Notice that the function:

Comes from certain transformations applied to the parent function absolute value:

There are 90 positive odd integers less than 1000 that can be formed from the digits 0, 1, 2, 3, 4, 5, and 6 by choosing any of the three odd digits as the last digit, and any of the remaining digits for the first and second positions.

To form a positive odd integer, the last digit must be an odd number, i.e., 1, 3, 5. For each of these three possible last digits, we can choose any of the remaining six digits for the first position, and any of the remaining five digits for the second position (since we cannot repeat digits in forming a positive integer).

Therefore, the total number of positive odd integers less than 1000 that can be formed from the digits 0, 1, 2, 3, 4, 5, and 6 is:

3 × 6 × 5 = 90

So there are 90 positive odd integers less than 1000 that can be formed from the given digits.

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Answer:

x = 7, y = 8

Step-by-step explanation:

Knowing y = 8, we can substitute into equation and solve:

8 = x + 1

- 1       - 1

7 = x

Y is given, X is solved. Therefore:

x = 7, y = 8