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3 years ago

Does anyone have a coursehero account that I can borrow

Mathematics

1 answer:

vagabundo [1.1K]3 years ago

5 0

Answer:

No but an easy way is to just make up random email names and passwords and on each acc u get 5 free questions,

Step-by-step explanation:

Can u pls mark me brainliest

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yoko pays $19.60 for a pack of 4 towels. find the unit price in dollars per towel if necessary round your answer to the nearest

Kazeer [188]

19.60/4=4.9
the answer is $4.90

6 0

2 years ago

Read 2 more answers

WHATS THE ANGLE MEASUREMENTS ?? & TELL HOW YOU GOT IT !!

sveticcg [70]

Answer:

ok ok i got u i thank lets go

1.78 or 5,600

Step-by-step explanation:

7x - 2= 14 m

5x - 10 = 100x

14x x 4x =56

now its two way it could be the 1st is

100 / 56 = 1.78

or 100 x 56 = 5,600

one of the two sorry o couldn't give u the full answer so one of the two

7 0

2 years ago

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Please help I don't know this and it's due today <br><br>5 - x = 12

attashe74 [19]

5 - x = 12

We're essentially just trying to get "x" onto its own side.

So, simply subtract 5 from both sides.

-x = 12 - 5

Simplify.

-x = 7

Now, divide both sides by -1.

x = -7

~Hope I helped!~

7 0

3 years ago

Leakage from underground gasoline tanks at service stations can damage the environment. It is estimated that 25% of these tanks

Gnesinka [82]

Answer:

a) 3.75

b) 23.61% probability that fewer than 3 tanks will be found to be leaking

c) 0% the probability that at least 600 of these tanks are leaking

Step-by-step explanation:

For each tank there are only two possible outcomes. EIther they leak, or they do not. The probability of a tank leaking is independent of other tanks. So we use the binomial probability distribution to solve this question.

Binomial probability 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.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

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

To solve question c), i am going to approximate the binomial distribution to the normal.

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 $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

It is estimated that 25% of these tanks leak.

This means that $p = 0.25$

15 tanks chosen at random

This means that $n = 15$

a.What is the expected number of leaking tanks in such samples of 15?

$E(X) = np = 15*0.25 = 3.75$

b.What is the probability that fewer than 3 tanks will be found to be leaking?

$P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)$

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

$P(X = 0) = C_{15,0}.(0.25)^{0}.(0.75)^{15} = 0.0134$

$P(X = 1) = C_{15,1}.(0.25)^{1}.(0.75)^{14} = 0.0668$

$P(X = 2) = C_{15,2}.(0.25)^{2}.(0.75)^{13} = 0.1559$

$P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0134 + 0.0668 + 0.1559 = 0.2361$

23.61% probability that fewer than 3 tanks will be found to be leaking

c.Now you do a larger study, examining a random sample of 2000 tanks nationally. What is the probability that at least 600 of these tanks are leaking?

Now we have n = 2000. So

$\mu = E(X) = np = 2000*0.25 = 500$