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2 years ago

In the library at Lenape Elementary School, there are

Mathematics

1 answer:

ValentinkaMS [17]2 years ago

5 0

Question:

In the library at Lenape Elementary School, there are 3/8 as many fiction books as there are nonfiction books. There are 44 books in the school library. How many books are fiction books?

Answer:

There are 12 fiction books in library

Solution:

Let "x" be the number of non fiction books

Then given that,

There are 3/8 as many fiction books as there are nonfiction books

$Fiction\ books = \frac{3}{8}x$

There are 44 books in the school library

Therefore,

Non fiction books + fiction books = 44

$x + \frac{3x}{8} = 44\\\\\8x + 3x = 44 \times 8\\\\11x = 44 \times 8\\\\x = 4 \times 8\\\\x = 32$

How many books are fiction books?

$Fiction\ books = \frac{3}{8}x = \frac{3 \times 32 }{8} = 12$

Thus there are 12 fiction books in library

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The lengths of the sides of triangle PQR are consecutive even integers. The perimeter of triangle PQR is 42 cm. What is the leng

Yuri [45]

Answer:

16 cm

Step-by-step explanation:

Let the three consecutive even integers representing the sides of the triangle PQR be x, (x +2) and (x + 4).

Since, perimeter of triangle PQR = 42 cm

$\therefore \: x + (x + 2) + (x + 4) = 42 \\ 3x + 6 = 42 \\ 3x = 42 - 6 \\ 3x = 36 \\ x = \frac{36}{3} \\ x = 12 \\ \\ \because \: longest \: side = x + 4 \\ \therefore \: longest \: side = 12 + 4 \\ \red{ \bold{ \therefore \: longest \: side = 16 \: cm}} \\$

6 0

1 year ago

Data sets A and B are dependent. Find sd.Assume that the paired data came from a population that is normally distributed.A. 1.73

marusya05 [52]

Complete question :

A : 2.7, 3.7, 5.6, 2.6, 2.7

B : 5.1, 4.0, 3.9, 3.8, 5.2

Data sets A and B are dependent. Find sd.Assume that the paired data came from a population that is normally distributed.A. 1.73B. 1.21C. 1.32D. 1.89

Answer: A.1.73

Step-by-step explanation:

Given the data:

A : 2.7, 3.7, 5.6, 2.6, 2.7

B : 5.1, 4.0, 3.9, 3.8, 5.2

Difference betweenA and B (A - B) :

Xd = (A - B) = - 2.4, -0.3, 1.7, - 1.2, - 2.5

Sum of (A - B) = Σ Xd = (-2.4 + (-0.3) + 1.7 + (-1.2) + (-2.5) = - 4. 7

Md = ΣXd / n = - 4.7 / 5 = - 0.94

Xd - Md = (-2.4 + 0.94), (-0.3 + 0.94), (1.7 + 0.94), (-1.2 + 0.94), (-2.5 + 0.94)

(Xd - Md) = - 1.46, 0.64, 2.64, - 0.26, - 1.56

(Xd - Md)^2 = (-1.46)^2 + 0.64^2 + 2.64^2 + (-0.26)^2 + (-1.56)^2

Σ(Xd - Md)^2 = (2.1316 + 0.4096 + 6.9696 + 0.0676 + 2.4336) = 12.012

Standard deviation = √[Σ(Xd - Md)^2 / (n-1)]

Standard deviation= √12.012 / 4

Standard deviation = 1.7329

Standard deviation= 1.73

3 0

2 years ago

Three assembly lines are used to produce a certain component for an airliner. To examine the production rate, a random sample of

nikitadnepr [17]

Answer:

a) Reject H₀

b) [0.31; 3.35]

Step-by-step explanation:

Hello!

a) The objective of this example is to compare if the population means of the production rate of the assembly lines A, B and C. To do so the data of the production of each line were recorded and an ANOVA was run using it.

The study variable is:

Y: Production rate of an assembly line.

Assuming that the study variable has a normal distribution for each population, the observations are independent and the population variances are equal, you can apply a parametric ANOVA with the hypothesis:

H₀ μ₁= μ₂= μ₃

H₁: At least one of the population means is different from the others

Where:

Population 1: line A

Population 2: line B

Population 3: line C

α: 0.01

This test is always one-tailed to the right. The statistic is the Snedecor's F, constructed as the MSTr divided by the MSEr if the value of the statistic is big, this means that there is a greater variance due to the treatments than to the error, this means that the population means are different. If the value of F is small, it means that the differences between populations are not significant ( may differ due to error and not treatment).

The critical region is:

$F_{k-1;n-k; 1-\alpha } = F_{2;15; 0.99} = 6.36$

If F ≥ 3.36, the decision is to reject the null hypothesis.

Looking at the given data:

$F= \frac{MSTr}{MSEr}$ = 11.32653

With this value the decision is to reject the null hypothesis.

Using the p-value method:

p-value: 0.001005

α: 0.01

The p-value is less than the significance level, the decision is to reject the null hypothesis.

At a level of 5%, there is significant evidence to say that at least one of the population means of the production ratio of the assembly lines A, B and C is different than the others.

b) In this item, you have to stop paying attention to the production ratio of the assembly line A to compare the population means of the production ratio of lines B and C.

(I'll use the same subscripts to be congruent with part a.)

The parameter to estimate is μ₂ - μ₃

The populations are the same as before, so you can still assume that the study variables have a normal distribution and their population variances are unknown but equal. The statistic to use under these conditions, since the sample sizes are 6 for both assembly lines, is a pooled-t for two independent variables with unknown but equal population variances.

t= (X[bar]₂ - X[bar]₃) - ( μ₂ - μ₃) ~t $_{n_2+n_3-2}$

Sa√(1/n₂+1/n₃)

The formula for the interval is:

(X[bar]₂ - X[bar]₃) ± $t_{n_2+n_3-2; 1 - \alpha /2}$ * $Sa\sqrt{*\frac{1}{n_2} + \frac{1}{n_3} }$

$Sa^{2} = \frac{(n_2-1)*S_2^2+ (n_3-1)*S_3^2}{n_2+n_3-2}$

$Sa^{2} = \frac{(5*0.67)+ (5*0.7)}{6+6-2}$

$Sa^{2} = 0.685$

Sa= 0.827 ≅ 0.83

$t_{n_2+n_3-2;1-\alpha /2}= t_{10;0.995} = 3.169$

X[bar]₂ = 43.33

X[bar]₃ = 41.5

(43.33-41.5) ± 3.169 * $*0.83\sqrt{*\frac{1}{6} + \frac{1}{6} }$

1.83 ± 3.169 * 0.479

[0.31; 3.35]

With a confidence level of 99% you'd expect that the difference of the population means of the production rate of the assemly lines B and C.

I hope it helps!

8 0

2 years ago

The parabola y=x^2y=x 2 y, equals, x, start superscript, 2, end superscript is reflected across the xxx-axis and then scaled ver

kramer

ANSWER

The equation of the new parabola is

$y = - 5 {x}^{2}$

EXPLANATION

The given parabola has equation:

$y = {x}^{2}$

If this parabola is reflected in the x-axis, its equation becomes :

$y = - {x}^{2}$

When this parabola is scaled vertically by a factor of 5, the equation becomes,

$y = - 5 {x}^{2}$

5 0

2 years ago

Julio wants to break his school’s scoring record of 864 points during his 24-game basketball season. During the first 8 games of

Scilla [17]

Answer:

x≥38 points

Step-by-step explanation:

Julio wants to break his school’s scoring record of 864 points during his 24-game basketball season. During the first 8 games of the season, he scored a total of 256 points. Which inequality can be used to find x, the number of points Julio must average per game during the rest of the season to break the record?

julio has a 24 game basketball season.

he has played 8, it means there are 16 more games to go

therefore=

he has scored 256 nts, wic means there are still 608 points to go .

864-256=608

x is the points he more score per every game.

16x=608

to break the records ,he must score an extra point 1

so 16x≥608

x≥38

8 0

1 year ago

Read 2 more answers