Can someone help me with this

Single adults: According to a Pew Research Center analysis of census data, in 2012, 20% of American adults ages 25 and older had

netineya [11]

Answer:

B. 50

Step-by-step explanation:

Central limit theorem is used to calculate the sampling distribution of the given case. The number of adults who are 25 years of age or above and not married is 20% of the samples selected. The standard deviation is 0.06 while the sample size should be 50 to conclude the results.

7 0

3 years ago

In a right triangle ABC, CD is an altitude, such that AD=BC. Find AC, if AB=3 cm, and CD= 2 cm.

konstantin123 [22]

Consider right triangle ΔABC with legs AC and BC and hypotenuse AB. Draw the altitude CD.

1. Theorem: The length of each leg of a right triangle is the geometric mean of the length of the hypotenuse and the length of the segment of the hypotenuse adjacent to that leg.

According to this theorem,

$BC^2=BD\cdot AB.$

Let BC=x cm, then AD=BC=x cm and BD=AB-AD=3-x cm. Then

$x^2=(3-x)\cdot 3,\\ \\x^2=9-3x,\\ \\x^2+3x-9=0,\\ \\D=3^2-4\cdot (-9)=9+36=45,\\ \\\sqrt{D}=\sqrt{45}=3\sqrt{5},\\ \\x_1=\dfrac{-3-3\sqrt{5} }{2}0.$

Take positive value x. You get

$AD=BC=\dfrac{-3+3\sqrt{5} }{2}\ cm.$

2. According to the previous theorem,

$AC^2=AD\cdot AB.$

Then

$AC^2=\dfrac{-3+3\sqrt{5} }{2}\cdot 3=\dfrac{-9+9\sqrt{5} }{2},\\ \\AC=\sqrt{\dfrac{-9+9\sqrt{5} }{2}}\ cm.$

Answer: $AC=\sqrt{\dfrac{-9+9\sqrt{5} }{2}}\ cm.$

This solution doesn't need CD=2 cm. Note that if AB=3cm and CD=2cm, then

$CD^2=AD\cdot DB,\\ \\2^2=AD\cdot (3-AD),\\ \\AD^2-3AD+4=0,\\ \\D$

This means that you cannot find solutions of this equation. Then CD≠2 cm.

8 0

4 years ago

Read 2 more answers

Write an equation of the line through (6,-2) with a slope of 4

torisob [31]

Notice that for this question, they are providing you with:

1) The slope of the line (4)

2) a point on the plane through which the line goes (6, -2)

So you can directly use for this the "point-slope" form of a line which is as follows:

$y-y_0=m(x-x_{0)}$

This includes m as the slope, and the pair (x0, y0) as the pair representing the point the line goes through.

So, let's use the info they gave you to complete this:

$y-(-2)=4(x-6)$

which we can work out a little more:

$y+2=4x-24$

And even a little more to finish the equation of the line in its standard slope-intercept form:

$y=4x-24-2=4x-26$

So the equation of the line is:

$y=4x-26$

3 0

1 year ago

Here is the charge at a car park in France.

anastassius [24]

Answer:

17:25

Step-by-step explanation:

assuming that 1315 is 13:15 for a 24 hour clock, then we divide 4.50 by 0.018 to get 250 which means that he parked for 250 minutes. then we convert it into 4 hours and 10 minutes then we get 17:25

5 0

3 years ago

Simplify the expression r^-3 s^5 t^2/r^2 st^-2

german

Hello here is a solution :

7 0

3 years ago