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3 years ago

Help Please Fast, simple

Mathematics

2 answers:

MAXImum [283]3 years ago

7 0

I’m not sure but it’s definitely not C

irinina [24]3 years ago

5 0

Answer:

Step-by-step explanation:

$KQ = PN$

We can't state that because we don't know if ∠NPK is 90º

Triangle KPN is similar to triangle KQN

It is the same case as the alternative a, we can't say the triangles are similar because we don't the angles for KPN. We know that LN is perpendicular to NP, but we don't if NP is perpendicular to PK, ∠NPK might be 89,9º, that is almost 90º.

KP = 0.5 LN

Once the four sides of the square are equal, LQ = QN. But from the picture we can only state that KP length is approximately the length of NQ (or 0.5 LN)

PN || KM

That's the correct answer! Once ∠QNP is 90º, PN is perpendicular to KM.

You might be interested in

∆XWZ≈∆______ by ________

Sergeeva-Olga [200]

I think triangle ZYX by asa

6 0

2 years ago

A selective college would like to have an entering class of 950 students. Because not all students who are offered admission acc

pogonyaev

Answer:

a) The mean is 900 and the standard deviation is 15.

b) 100% probability that at least 800 students accept.

c) 0.05% probability that more than 950 will accept.

d) 94.84% probability that more than 950 will accept

Step-by-step explanation:

We use the normal approximation to the binomial to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

(a) What are the mean and the standard deviation of the number X of students who accept?

$n = 1200, p = 0.75$ . So

$E(X) = np = 1200*0.75 = 900$

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{1200*0.75*0.25} = 15$

The mean is 900 and the standard deviation is 15.

(b) Use the Normal approximation to find the probability that at least 800 students accept.

Using continuity corrections, this is $P(X \geq 800 - 0.5) = P(X \geq 799.5)$ , which is 1 subtracted by the pvalue of Z when X = 799.5. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{799.5 - 900}{15}$

$Z = -6.7$

$Z = -6.7$ has a pvalue of 0.

1 - 0 = 1

100% probability that at least 800 students accept.

(c) The college does not want more than 950 students. What is the probability that more than 950 will accept?

Using continuity corrections, this is $P(X \geq 950 - 0.5) = P(X \geq 949.5)$ , which is 1 subtracted by the pvalue of Z when X = 949.5. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{949.5 - 900}{15}$

$Z = 3.3$

$Z = 3.3$ has a pvalue of 0.9995

1 - 0.9995 = 0.0005

0.05% probability that more than 950 will accept.

(d) If the college decides to increase the number of admission offers to 1300, what is the probability that more than 950 will accept?

Now n = 1300. So

$E(X) = np = 1300*0.75 = 975$

$\sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{1200*0.75*0.25} = 15.6$

Same logic as c.

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{949.5 - 975}{15.6}$

$Z = -1.63$

$Z = -1.63$ has a pvalue of 0.0516

1 - 0.0516 = 0.9484

94.84% probability that more than 950 will accept

5 0

3 years ago

Which of the following equations is in equation formed when completing the square on y^2 - 12 y= -27

bogdanovich [222]

Answer:

$(y-6)^2=9$

Step-by-step explanation:

Given

$y^2 - 12y = -27$

Required

Get equivalent expression using completing the square

Follow these steps:

Take the coefficient of y; That is -12

Divide it by 2; That is (-12/2)

Square it: (-12/2)^2

Add to both sides of the equation

$y^2 - 12y + (\frac{-12}{2})^2= -27 + (\frac{-12}{2})^2$

$y^2 - 12y + (-6)^2= -27 + (-6)^2$

$y^2 - 12y + 36= -27 + 36$

$y^2 - 12y + 36= 9$

Expand the right-hand side

$y^2 - 6y - 6y + 36= 9$

Factorize:

$y(y-6)-6(y-6) =9$

$(y-6)(y-6)=9$

$(y-6)^2=9$

5 0

3 years ago

it takes allison ten minutes to fill a dozen water balloons she wants to calculate how long it will take her to fill all the wat

nadezda [96]

Well you need an equation because how many friends were at the party? x*12x10=w thats your equation or however you want to put it. the letters are your variables

4 0

3 years ago

Read 2 more answers

Which is the best first step and explanation for solving this system of equations? 3x+4y=12 3x=2y-8

Greeley [361]

Answer:

Since it is a simultaneous equation,

Using elimination method, Multiply equation 1 by the co efficient of x in equation 2 and multiply equation 2 by the co efficient of x in equation 1.

Step-by-step explanation:

For further explanation , Please contact me through the comment section.

6 0

3 years ago