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Nikitich [7]
3 years ago
15

URGENT HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mathematics
2 answers:
Ganezh [65]3 years ago
8 0

Answer: Gaira made a mistake when substituting the value –7.5 in for x. She multiplied both terms of the expression by –7.5 when she should have only multiplied –3.8 by –7.5. The correct answer is 34.5.

Step-by-step explanation:edginuity

Nimfa-mama [501]3 years ago
5 0
The mistake she made was timesing the 6 by the -7.5 as there is no x after the 6
Therefore:

-3.8(-7.5) +6
28.5+6 =34.5
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Cicily wants to estimate the answer to this problem to see if her answer is reasonable.
suter [353]
I believe that the answer is A- 8600-5300
Hope this helps!
3 0
3 years ago
A fair coin is to be tossed 20 times. Find the probability that 10 of the tosses will fall heads and 10 will fall tails, (a) usi
lbvjy [14]

Using the distributions, it is found that there is a:

a) 0.1762 = 17.62% probability that 10 of the tosses will fall heads and 10 will fall tails.

b) 0% probability that 10 of the tosses will fall heads and 10 will fall tails.

c) 0.1742 = 17.42% probability that 10 of the tosses will fall heads and 10 will fall tails.

Item a:

Binomial probability distribution

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

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

The parameters are:

  • x is the number of successes.
  • n is the number of trials.
  • p is the probability of a success on a single trial.

In this problem:

  • 20 tosses, hence n = 20.
  • Fair coin, hence p = 0.5.

The probability is <u>P(X = 10)</u>, thus:

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

P(X = 10) = C_{20,10}.(0.5)^{10}.(0.5)^{10} = 0.1762

0.1762 = 17.62% probability that 10 of the tosses will fall heads and 10 will fall tails.

Item b:

In a normal distribution with mean \mu and standard deviation \sigma, the z-score of a measure X is given by:

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

  • It 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, which is the percentile of X.
  • The binomial distribution is the probability of <u>x successes on n trials, with p probability</u> of a success on each trial. It can be approximated to the normal distribution with \mu = np, \sigma = \sqrt{np(1-p)}.

The probability of an exact value is 0, hence 0% probability that 10 of the tosses will fall heads and 10 will fall tails.

Item c:

For the approximation, the mean and the standard deviation are:

\mu = np = 20(0.5) = 10

\sigma = \sqrt{np(1 - p)} = \sqrt{20(0.5)(0.5)} = \sqrt{5}

Using continuity correction, this probability is P(10 - 0.5 \leq X \leq 10 + 0.5) = P(9.5 \leq X \leq 10.5), which is the <u>p-value of Z when X = 10.5 subtracted by the p-value of Z when X = 9.5.</u>

X = 10.5:

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

Z = \frac{10.5 - 10}{\sqrt{5}}

Z = 0.22

Z = 0.22 has a p-value of 0.5871.

X = 9.5:

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

Z = \frac{9.5 - 10}{\sqrt{5}}

Z = -0.22

Z = -0.22 has a p-value of 0.4129.

0.5871 - 0.4129 = 0.1742.

0.1742 = 17.42% probability that 10 of the tosses will fall heads and 10 will fall tails.

A similar problem is given at brainly.com/question/24261244

6 0
3 years ago
If x^2 - 6x +8=0, then x-4=0 or x-2=0.
Dimas [21]

Step-by-step explanation:

X - 4 = 0

X = 4

X - 2 = 0

X = 2

So the values of x are 2 and 4

4 0
3 years ago
I need help on this
Marina CMI [18]

I think it's answer choice a

3 0
3 years ago
Read 2 more answers
Under her cell phone plan, Janelys pays a flat cost of $46.50 per month and $5 per gigabyte. She wants to keep her bill under $7
allsm [11]

Answer:

Less than 4.70 GB

Step-by-step explanation:

Let x = # of GB that Janelys uses that month. Since Janelys wants to pay less than $70 given that the flat rate for subscribing to that company's data per month is $46.50 and each GB costs $5 to use, the inequality can be written as:

5x + 46.50 < 70

5x < 23.50                        Subtract $45.60 from each side.

x < 4.70 GB                       Divide 5 from each side.

Thus, (if it is whole numbers) Janelys can use 4 GB while staying within her budget or (if decimals are fine) anything less than 4.70 GB. Hope this helped! :D

8 0
3 years ago
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