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3 years ago

Can I get a little help on this problem?

Mathematics

1 answer:

andrey2020 [161]3 years ago

5 0

Hello from MrBillDoesMath!

Answer:

12/55

Discussion:

Start by simplifying the numerator:

( 3/(5b) - 2/(5b)) / ( 1/(4b) + 2/(3b) ) = => as 3/(5b)- 2/(5b) = 1/(5b)

(1/(5b) / (1/(4b) + 2/(3b) ) = => multiply num., denom. by "b"

(b * 1/(5b)) / ( b/(4b) +2b/(3b)) = => as b/b = 1

(1/5) / (1/4 + 2/3) = => 1/4 = 3/12; 2/3 = 8/12

(1/5)/ ( 3/12 + 8/12) =

(1/5)/ ( 11/12) = => 1/ (11/12) = 12/11

(1/5) 12/11 =

12/55

Thank you,

MrB

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A random sample of 130 students is chosen from a population of 4,500 students. The mean IQ in the sample is 120, with a standard

barxatty [35]

Answer:

$120-2.614\frac{5}{\sqrt{130}}=118.85$

$120+2.614\frac{5}{\sqrt{130}}=121.15$

Step-by-step explanation:

Information given

$\bar X= 120$ represent the sample mean

$\mu$ population mean (variable of interest)

s=5 represent the sample standard deviation

n=130 represent the sample size

For this case we can't set a margin of error just with a % since they not specify 1.13% respect to something for this case we can omit this value

Confidence interval

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

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

The degrees of freedom are given by:

$df=n-1=130-1=129$

The Confidence level is 0.99 or 99%, the significance would be $\alpha=0.01$ and $\alpha/2 =0.005$ , and the critical value would be $t_{\alpha/2}=2.614$

And replacing we got:

$120-2.614\frac{5}{\sqrt{130}}=118.85$

$120+2.614\frac{5}{\sqrt{130}}=121.15$

3 0

3 years ago

Which of the following represents an equation of a line that has an x-intercept of 8 and a y-intercept of 2?

Julli [10]

Correct answer A) x+4y=8 , represents an equation of a line that has an x-intercept of 8 and a y-intercept of 2 .

Step-by-step explanation:

Here we have to identify Which of the following represents an equation of a line that has an x-intercept of 8 and a y-intercept of 2 .Let's find out:

A) x+4y=8

Let's check if line has an x-intercept of 8 i.e. at y=0 value of x is 8 :

⇒ $x+4y=8$

⇒ $x+4(0)=8$

⇒ $x=8$

Let's check if line has an y-intercept of 2 i.e. at x=0 value of y is 2 :

⇒ $x+4y=8$

⇒ $0+4(y)=8$

⇒ $y=2$

Hence , Correct option!

B) x=(-.25y+2)

Let's check if line has an x-intercept of 8 i.e. at y=0 value of x is 8 :

⇒ $x=(-.25y+2)$

⇒ $x=(-.25(0)+2)$

⇒ $x=2$

Incorrect option!

C) 4x+y=2

Let's check if line has an x-intercept of 8 i.e. at y=0 value of x is 8 :

⇒ $4x+y=2$

⇒ $4x+0=2$

⇒ $x=\frac{1}{2}$

Incorrect option!

D) y=-4x+8

Let's check if line has an x-intercept of 8 i.e. at y=0 value of x is 8 :

⇒ $y=-4x+8$

⇒ $0=-4x+8$

⇒ $x=2$

Incorrect option!

8 0

3 years ago

Read 2 more answers

What is the surface area of the rectangular prism? 480mm 427mm 213.5mm 255mm

elena-14-01-66 [18.8K]

The surface area of the rectangular prism is 427 mm². The correct option is the second option 427 mm²

<h3>Calculating surface area</h3>

From the question, we are to calculate the surface area of the rectangular prism

Surface area of a rectangular prism can be calculated by using the formula,

Surface area = 2(lw + lh + wh)

Where l is the length

w is the width

and h is the height

In the given diagram,

l = 21.5 mm

w = 4 mm

h = 5 mm

Putting the parameters into the equation, we get

Surface area = 2(21.5×4 + 21.5×5 + 4×5)

Surface area = 2(86 + 107.5 + 20)

Surface area = 2 × 213.5

Surface area = 427 mm²

Hence, the surface area of the rectangular prism is 427 mm². The correct option is the second option 427 mm²

Learn more on Surface area here: brainly.com/question/1310421

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7 0

2 years ago

What binomial do you have to add to the polynomial:

marshall27 [118]

Answer:

a) $-2x^2+5xy$

b) $-3y^2+5xy$

Step-by-step explanation:

Part (a)

Given polynomial : $2x^2+3y^2-5xy+1$

The binomial that should be added to the given polynomial to get a polynomial that does not contain the variable x is:

$-2x^2+5xy$

$(2x^2+3y^2-5xy+1)+(-2x^2+5xy)$

$=2x^2+3y^2-5xy+1-2x^2+5xy$

$=2x^2-2x^2+3y^2-5xy+5xy+1$

$=3y^2+1$

Part (b)

Given polynomial : $2x^2+3y^2-5xy+1$

The binomial that should be added to the given polynomial to get a polynomial that does not contain the variable y is:

$-3y^2+5xy$

$(2x^2+3y^2-5xy+1)+(-3y^2+5xy)$

$=2x^2+3y^2-5xy+1-3y^2+5xy$

$=2x^2+3y^2-3y^2-5xy+5xy+1$

$=2x^2+1$

7 0

2 years ago

The circle shown below has a diameter of 18 centimeters. What is the area of the shaded sector?

N76 [4]

Area of circle = Pi x r*2

If diameter is 18, radius is 9.

Area = pi (3.14) x r*2 (9*2 = 81) .. 3.14 x 81 = 254.34 sq cen = total area of circle.

A circle is 360 degrees, the shaded area is 270 degrees. the shaded area is 3/4 (270/360) of the area of the circle.

254.34 x 3/4 = 190.755 sq cen

Hope this helps

7 0

3 years ago

Read 2 more answers