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masya89 [10]
3 years ago
11

What is 9 more than y

Mathematics
1 answer:
Volgvan3 years ago
6 0
9 more than y is an expression so it would be 9+y
You might be interested in
Mike has $25.00 to rent paddleboards for himself and a friend for 3 hours. Each paddleboard rental costs $3.75 per hour.use the
Verdich [7]

Mike ($3.75): x

Friends ($3.75): 3x

Mike   +  Friends   ≤  25

3.75(x) + 3.75(3x)  ≤ 25

3.75x  +  11.25x   ≤ 25

                15x      ≤ 25

                 \frac{15x}{15}      ≤  \frac{25}{15}

                  x        ≤ 1\frac{2}{3}

Answer: they can rent the paddleboards for 1 hour 40 minutes

7 0
3 years ago
After a large scale earthquake, it is predicted that 15% of all buildings have been structurally compromised.a) What is the prob
Westkost [7]

Answer:

a) 13.68% probability that if engineers inspect 20 buildings they will find exactly one that is structurally compromised.

b) 17.56% probability that if engineers inspect 20 buildings they will find less than 2 that are structurally compromised

c) 17.02% probability that if engineers inspect 20 buildings they will find greater than 4 that are structurally compromised

d) 75.70% probability that if engineers inspect 20 buildings they will find between 2 and 5 (inclusive) that are structurally compromised

e) The expected number of buildings that an engineer will find structurally compromised if the engineer inspects 20 buildings is 3.

Step-by-step explanation:

For each building, there are only two possible outcomes after a earthquake. Either they have been damaged, or they have not. The probability of a building being damaged is independent from other buildings. 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.

15% of all buildings have been structurally compromised.

This means that p = 0.15

20 buildings

This means that n = 20

a) What is the probability that if engineers inspect 20 buildings they will find exactly one that is structurally compromised?

This is P(X = 1).

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

P(X = 1) = C_{20,1}.(0.15)^{1}.(0.85)^{19} = 0.1368

13.68% probability that if engineers inspect 20 buildings they will find exactly one that is structurally compromised.

b) What is the probability that if engineers inspect 20 buildings they will find less than 2 that are structurally compromised?

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

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

P(X = 0) = C_{20,0}.(0.15)^{0}.(0.85)^{20} = 0.0388

P(X = 1) = C_{20,1}.(0.15)^{1}.(0.85)^{19} = 0.1368

P(X < 2) = P(X = 0) + P(X = 1) = 0.0388 + 0.1368 = 0.1756

17.56% probability that if engineers inspect 20 buildings they will find less than 2 that are structurally compromised

c) What is the probability that if engineers inspect 20 buildings they will find greater than 4 that are structurally compromised?

Either they find 4 or less, or they find more than 4. The sum of the probabilities of these events is 1. So

P(X \leq 4) + P(X > 4) = 1

P(X > 4) = 1 - P(X \leq 4)

In which

P(X \leq 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4)

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

P(X = 0) = C_{20,0}.(0.15)^{0}.(0.85)^{20} = 0.0388

P(X = 1) = C_{20,1}.(0.15)^{1}.(0.85)^{19} = 0.1368

P(X = 2) = C_{20,2}.(0.15)^{2}.(0.85)^{18} = 0.2293

P(X = 3) = C_{20,3}.(0.15)^{3}.(0.85)^{17} = 0.2428

P(X = 4) = C_{20,4}.(0.15)^{4}.(0.85)^{16} = 0.1821

P(X \leq 4) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) = 0.0388 + 0.1368 + 02293 + 0.2428 + 0.1821 = 0.8298

P(X > 4) = 1 - P(X \leq 4) = 1 - 0.8298 = 0.1702

17.02% probability that if engineers inspect 20 buildings they will find greater than 4 that are structurally compromised

d) What is the probability that if engineers inspect 20 buildings they will find between 2 and 5 (inclusive) that are structurally compromised?

P(2 \leq X \leq 5) = P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)

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

P(X = 2) = C_{20,2}.(0.15)^{2}.(0.85)^{18} = 0.2293

P(X = 3) = C_{20,3}.(0.15)^{3}.(0.85)^{17} = 0.2428

P(X = 4) = C_{20,4}.(0.15)^{4}.(0.85)^{16} = 0.1821

P(X = 5) = C_{20,5}.(0.15)^{5}.(0.85)^{15} = 0.1028

P(2 \leq X \leq 5) = P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.2293 + 0.2428 + 0.1821 + 0.1028 = 0.7570

75.70% probability that if engineers inspect 20 buildings they will find between 2 and 5 (inclusive) that are structurally compromised

e) What is the expected number of buildings that an engineer will find structurally compromised if the engineer inspects 20 buildings?

The expected value of the binomial distribution is:

E(X) = np

So

E(X) = 20*0.15 = 3

The expected number of buildings that an engineer will find structurally compromised if the engineer inspects 20 buildings is 3.

3 0
3 years ago
According to a Pew Research Center, in May 2011, 35% of all American adults had a smart phone (one which the user can use to rea
Veronika [31]

Answer:

p_v =P(z>1.82)=0.034  

Assuming a standard significance level of \alpha=0.05 the best conclusion for this case would be:

4. There is not enough evidence to show that more than 35% of community college students own a smart phone (P-value = 0.034).

Because p_v

If we select a significance level lower than 0.034 then the conclusion would change.

Step-by-step explanation:

Data given

n=300 represent the random sample taken

X=120 represent the people who have a smart phone

\hat p=\frac{120}{300}=0.4 estimated proportion of people who have a smart phone

p_o=0.35 is the value that we want to test

z would represent the statistic (variable of interest)

p_v represent the p value (variable of interest)  

System of hypothesis

We need to conduct a hypothesis in order to test the claim that the true proportion of people who have a smart phone is higher than 0.35, the system of hypothesis are.:  

Null hypothesis:p\leq 0.35  

Alternative hypothesis:p > 0.35  

The statistic is given by:

z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}} (1)  

Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

z=\frac{0.4 -0.35}{\sqrt{\frac{0.35(1-0.35)}{300}}}=1.82  

Statistical decision  

Since is a right tailed test the p value would be:  

p_v =P(z>1.82)=0.034  

Assuming a standard significance level of \alpha=0.05 the best conclusion for this case would be:

4. There is not enough evidence to show that more than 35% of community college students own a smart phone (P-value = 0.034).

Because p_v

If we select a significance level lower than 0.034 then the conclusion would change.

4 0
3 years ago
The sum of a number and forty-six
ad-work [718]

\textsf{Hey there!}

\mathsf{\star \ The\ sum\ of\ a\ number\ \&\  forty-six}

\frak{Let's\ lable\ the\ keypoints\ so\ it\ can\ be\ easier\ to\ solve}

\bullet \ \textsf{The word \bf{\underline{SUM}}}\textsf{\ means\ add/addition}}

\bullet\textsf{ \underline{"A number"} is an unknown number so we can lable it as \bf{x}}

\bullet\textsf{ \underline{forty-six} is 46}

\textsf{The sum (+) does in the middle while \underline{x} \& \underline{46} will either be on left/right}

- \ \textsf{We can say that x is on your left}

-\  \textsf{  + can be in your middle}

- \ \textsf{\& lastly 46 can be on your right}

\boxed{\textsf{Thus, your answer SHOULD LOOK like: \boxed{\huge\text{\bf{x + 46}}}}}\checkmark

\textsf{Good luck on your assignment and enjoy your day!}

~\frak{LoveYourselfFirst:)}

4 0
3 years ago
X^2-x+12 solve using the quadratic formula
devlian [24]

The quadratic formula is x=\frac{-b\pm\sqrt{b^2-4ac} }{2a}.

From the problem, a is 1, b is -1, and c is 12. Plugging in these values gives:

x=\frac{-(-1(-1)\pm\sqrt{(-1)^2-4(1)(12)} }{2(1)}

Because there is a square root of a negative number, there is no solution.

4 0
3 years ago
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