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4 years ago

Guys please help me with my homework

Mathematics

2 answers:

solmaris [256]4 years ago

8 0

3 sandwiches and 5 lemonades

Alika [10]4 years ago

6 0

3 sandwiches and 5 lemonades

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What addition doubles fact can help you find 4+3? Explain how you kbow

Shalnov [3]

1111 + 111 = 7
2+2+111=7
2+2+3=7

3 0

3 years ago

A rectangular plot of land that contains 1500 square meters will be fenced and divided into two equal portions by an additional

WINSTONCH [101]

Let x = the length of the rectangle
Let w= the width

Two sections are required, hence 2w of fence required
2x+3w=500

this can be written as:
3w=1500-2x
w=(1500-2x)/3

Area=x*w
replacing w with our expression:
A=x(1500-2x)/3
A=(500x-2x^2)/3

This is a quadratic equation, if we find the axis of symmetry we will know what value of x gives maximum area:
Axis of symmetry: x=-b/2a
From our equation we get:
a=-2/3; b=1500/3
thus
x=(1500/3)/(-(-2/3))
x=750
thus the maximum area will be given by length of 750

3 0

4 years ago

Express p/q form of 0.375

expeople1 [14]

Answer:

15/40

Step-by-step explanation:

$0.375 = \frac{375}{1000} \\ \\ = \frac{15}{40}$

5 0

3 years ago

Please help I’ll mark Brainly

olga55 [171]

Answer:

b. all real numbers

Step-by-step explanation:

every value of x f(x) is defined

8 0

3 years ago

A random sample of ten 2011 sports cars is taken and their city mileage is recorded. The results are as follows: 20 21 25 21 21

serious [3.7K]

Answer:

$ME = 1.833 * \frac{4.367}{\sqrt{10}}= 2.531$

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)}{n-1}}$ (3)

The mean calculated for this case is $\bar X=24.8$

The sample deviation calculated $s=4.367$

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=10-1=9$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,9)".And we see that $t_{\alpha/2}=1.833$

And the margin of error would be given by:

$ME = 1.833 * \frac{4.367}{\sqrt{10}}= 2.531$

5 0

4 years ago