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Valentin [98]
3 years ago
7

A middle school has 470 students. Regina surveys a random sample of 40 students and finds that 28 have cell phones. How many stu

dents at the school are likely to have cell phones?
Mathematics
2 answers:
nikitadnepr [17]3 years ago
5 0
The answer is 329. If you set this up as a proportion you get 28/40=x/470 then you cross multiply 28x470 to get 13,160 and decide it by 40 to get 329
Dmitry [639]3 years ago
4 0
So from that i think the formula would be
\frac{x}{470}  =  \frac{28}{40}
so then you find "x" by multiplying 470 x 28 which equals 13,160. Then you divide 13,160 by 40 which equals 329.
X=329
329 students are likely to have phones

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Find (if possible) the complement and the supplement of each angle. (if not possible, enter impossible.) (a) π 10 complement rad
blagie [28]

In this question, we have to find the complement and supplement of the given angles .

Complementary angles are those angles whose sum is 90 degree and supplementary angles are those angles whose sum is 180 degree.

So to find the complement and supplement angles, we need to subtract the given angles from pi/2 and pi respectively .

a.

\frac{ \pi}{10}
\\
complement  \ angle = \frac{ \pi}{2} - \frac{ \pi}{10}     \\                             = \frac{4 \pi}{10} = \frac{ 2 \pi}{5}
\\
Supplement  \ angle = \pi - \frac{ \pi}{10} = \frac{9 \pi}{10}

b.

\frac{9 \pi}{10}
\\
Complement \ angle = \frac{ \pi}{2} - \frac{9 \pi}{10} = \frac{-4 \pi}{10} = -\frac{2 \pi}{5}
\\
Supplement \ angle = \pi - \frac{9 \pi}{10} = \frac{ \pi}{10}

4 0
3 years ago
So, for context my teacher said it's C but I don't understand how the slope is negative.​
Lelechka [254]

the answer is:

A. slope: 9, y-intercept: -6

6 0
3 years ago
Refer to your Expeditions in Reading book for a complete version of this text.
ahrayia [7]

Answer:

The 3rd one, The 1st one and The last one.

Step-by-step explanation:

6 0
2 years ago
Consider writing onto a computer disk and then sending it through a certifier that counts the number of missing pulses. Suppose
Furkat [3]

Answer:

a) 0.164 = 16.4% probability that a disk has exactly one missing pulse

b) 0.017 = 1.7% probability that a disk has at least two missing pulses

c) 0.671 = 67.1% probability that neither contains a missing pulse

Step-by-step explanation:

To solve this question, we need to understand the Poisson distribution and the binomial distribution(for item c).

Poisson distribution:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}


In which

x is the number of sucesses


e = 2.71828 is the Euler number

\mu is the mean in the given interval.

Binomial distribution:

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

In which C_{n,x} is the number of different combinations of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

And p is the probability of X happening.

Poisson mean:

\mu = 0.2

a. What is the probability that a disk has exactly one missing pulse?

One disk, so Poisson.

This is P(X = 1).

P(X = 1) = \frac{e^{-0.2}*0.2^{1}}{(1)!} = 0.164


0.164 = 16.4% probability that a disk has exactly one missing pulse

b. What is the probability that a disk has at least two missing pulses?

P(X \geq 2) = 1 - P(X < 2)

In which

P(X < 2) = P(X = 0) + P(X = 1)

In which

P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}&#10;

P(X = 0) = \frac{e^{-0.2}*0.2^{0}}{(0)!} = 0.819

P(X = 1) = \frac{e^{-0.2}*0.2^{1}}{(1)!} = 0.164&#10;

P(X < 2) = P(X = 0) + P(X = 1) = 0.819 + 0.164 = 0.983

P(X \geq 2) = 1 - P(X < 2) = 1 - 0.983 = 0.017

0.017 = 1.7% probability that a disk has at least two missing pulses

c. If two disks are independently selected, what is the probability that neither contains a missing pulse?

Two disks, so binomial with n = 2.

A disk has a 0.819 probability of containing no missing pulse, and a 1 - 0.819 = 0.181 probability of containing a missing pulse, so p = 0.181

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P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 0) = C_{2,0}.(0.181)^{0}.(0.819)^{2} = 0.671

0.671 = 67.1% probability that neither contains a missing pulse

8 0
3 years ago
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True [87]

Answer:


Step-by-step explanation:

Given line is,

y=-4x+3

when, x=-1 , y=-4(-1)+3=4+3=7

when, x=0 , y=-4(0)+3=0+3=3

when, x=1 , y=-4(1)+3=-4+3=-1

So, we got the points  (-1,7) , (0,3) , (1,-1)

Now, putting the points in the graph and adding them , we will get the graph of given line.

Please check image for the graph.


Now for the second part-

The graph is positive means- it will be above the x-axis, that is y value will be positive.

From the graph we can see that, if x<0 , then y is positive.

So, any value of x which is less than 0 , will give the positive graph here.

6 0
3 years ago
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