What’s the correct answer for this question?

Answer:

[tex]P(x>20)=9.67*10^{-10}[/tex]

Step-by-step explanation:

If we call x the number of correct answers, we can said that P(x) follows a Binomial distribution, because we have 25 questions that are identical and independent events with a probability of 1/4 to success and a probability of 3/4 to fail.

So, the probability can be calculated as:

[tex]P(x)=nCx*p^{x}*q^{n-x}=25Cx*0.25^{x}*0.75^{25-x}[/tex]

Where n is 25 questions, p is the probability to success or 0.25 and q is the probability to fail or 0.75.

Additionally, [tex]25Cx=\frac{25!}{x!(25-x)!}[/tex]

So, the probability that the student answers more than 20 questions correctly is equal to:

[tex]P(x>20)=P(21)+P(22)+P(23)+P(24)+P(25)[/tex]

Where, for example, P(21) is equal to:

[tex]P(21)=25C21*0.25^{21}*0.75^{25-21}=9.1*10^{-10}[/tex]

Finally, P(x>20) is equal to:

[tex]P(x>20)=9.67*10^{-10}[/tex]

Answer:

53

Step-by-step explanation:

8•7 is 56

56 - 3 is 53

Answer:

53

Step-by-step explanation:

z = 7

8z is the same as saying 8×z

8×7-3 (do multiplication first)

56-3 = 53

Answer:

a. 50 turns

b. 0.0114 A

c. 0.25 A, 10 V

Step-by-step explanation:

Given:-

- The required current ( Is ) = 0.5 A

- The required voltage ( Vs ) = 5 V

- Transformer is 100% efficient ( ideal )

- The number of turns in the primary coil, ( Np ) = 2200

- The Voltage generated by power station, ( Vp ) = 220 V

Find:-

a. The number of turns in the secondary coil of the transformer

b. The current supplied by the power station

c. The effect on output current and voltage when the number of turns of secondary coil are doubled.

Solution:-

- For ideal transformers that consists of a ferromagnetic core with two ends wounded by a conductive wire i.e primary and secondary.

- The power generated at the stations is sent to home via power lines and step-down before the enter our homes.

- A household receives a voltage of 220 V at one of it outlets. We are to charge a phone that requires 0.5 A and 5V for the process.

- The outlet and any electronic device is in junction with a smaller transformer.

- All transformers have two transformation ratios for current ( I ) and voltage ( V ) that is related to the ratio of number of turns in the primary and secondary.

                     Voltage Transformation = [tex]\frac{N_p}{N_s} = \frac{V_p}{V_s}[/tex]

Where,

                 Ns : The number of turns in secondary winding

- Plug in the values and evaluate ( Ns ):

                           [tex]N_s = N_p*\frac{V_s}{V_p} \\\\N_s = 2200*\frac{5}{220} \\\\N_s = 50[/tex]

Answer a: The number of turns in the secondary coil should be Ns = 50 turns.

- Similarly, the current transformation is related to the inverse relation to the number of turns in the respective coil.

                  Current Transformation = [tex]\frac{N_p}{N_s} = \frac{I_s}{I_p}[/tex]

Where,

                 Ip : The current in primary coil

- Plug in the values and evaluate ( Ip ):

                        [tex]I_p = \frac{N_s}{N_p}*I_s\\\\I_p = \frac{50}{2200}*0.5\\\\I_p = 0.0114[/tex]  

Answer b: The current in the primary coil should be Ip = 0.0114 Amp.

- The number of turns in the secondary coil are doubled . From the transformation ratios we know that that voltage is proportional to the number of turns in the respective coils. So if the turns in the secondary are doubled then the output voltage is also doubled ( assuming all other design parameters remains the same ). Hence, the output voltage is = 2*5V = 10 V

- Similary, current transformation ratio suggests that the current is inversely proportional to the number of turns in the respective coils. So if the turns in the secondary are doubled then the output current is half of the required ( assuming all other design parameters remains the same ). Hence, the output current is = 0.5*0.5 A = 0.25 A

Answer:

2.54 seconds

Step-by-step explanation:

We can use the following equation to model the vertical position of the ball:

S = So + Vo*t + a*t^2/2

Where S is the final position, So is the inicial position, Vo is the inicial speed, a is the acceleration and t is the time.

Then, using S = 2.5, So = 0.4, Vo = 14 and a = -9.8 m/s2, we have that:

2.5 = 0.4 + 14*t - 4.9t^2

4.9t^2 - 14t + 2.1 = 0

Solving this quadratic equation, we have that t1 = 2.6983  s and t2 = 0.1588 s.

Between these times, the ball will be higher than 2.5 m, so the amount of time the ball will be higher than 2.5 m is:

t1 - t2 = 2.6983  - 0.1588 = 2.54 seconds

Answer:

y=cosx

Step-by-step explanation:

cosx has a domain of all real numbers

Answer:

D. Pilot error isPilot error is the most serious threat to aviation safety. Pilots could be better trained.

Step-by-step explanation:

We can construct the relative frequency distribution dividing the amount of incidents for each category by the total amount of incidents.

This amount is:

[tex]\sum x_i=627+64+113+382+481=1667[/tex]

Then, the relative frequency for each category is:

[tex]\text{Pilot error}=627/1667=0.38\\\\\text{Human error}=64/1667=0.04\\\\\text{Weather}=113/1667=0.07\\\\\text{Mechanical problems}=382/1667=0.23\\\\\text{Sabotage}=481/1667=0.29\\\\[/tex]

As the pilot error has the largest relative frequency, we can conclude that pilot error is the most serious threat to aviation safety.

Answer:

C.

Step-by-step explanation:

First finding height using Pythagoras theorem

(H)²=(B)²+(P)²

8.2²=5.4²+P²

P² = 67.24 - 29.16

P² = 38.08

P = 6.2

Now

Volume of cone = (1/3)πr²h

= (1/3)(3.14)(5.4)²(6.2)

= (1/3)(567.9)

= 189.2 cm³

Well lets see.

[tex]3(x+4)=3x+4\implies 12 = 4\implies x\notin\mathbb{C}[/tex].

There are no such x-es that satisfy the equation.

Answer:

z=12500

Step-by-step explanation:

Of means multiply and is means equals

85% *z = 106250

Change to decimal form

.85z = 106250

Divide each side by .85

.85z/.85 = 106250 /.85

z=12500

Answer:

The probability that a study participant has a height that is less than 65 inches is 0.1103.

Step-by-step explanation:

We are given that the heights in the​ 20-29 age group were normally​ distributed, with a mean of 69.9 inches and a standard deviation of 4.0 inches.

A study participant is randomly selected.

Let X = heights in the​ 20-29 age group.

So, X ~ Normal([tex](\mu=69.9,\sigma^{2} =4.0^{2}[/tex])

The z-score probability distribution for the normal distribution is given by;

                             Z  =  [tex]\frac{X-\mu}{\sigma}[/tex]  ~ N(0,1)

where, [tex]\mu[/tex] = mean height = 69.9 inches

           [tex]\sigma[/tex] = standard deviation = 4.0 inches

Now, the probability that a study participant has a height that is less than 65 inches is given by = P(X < 65 inches)

      P(X < 65 inches) = P( [tex]\frac{X-\mu}{\sigma}[/tex] < [tex]\frac{65-69.9}{4}[/tex] ) = P(Z < -1.225) = P(Z [tex]\leq[/tex] 1.225)

                                                                 =  1 - 0.8897 = 0.1103

The above probability is calculated by looking at the value of x = 1.225 in the z table which lies between x = 1.22 and x = 1.23 which has an area of 0.88877 and 0.89065 respectively.

Answer:

B.

Step-by-step explanation:

A cone with a radius of 1-unit will be obtained by rotating the 3-D figure.

Answer:

62.93%

Step-by-step explanation:

We have to solve it by a Poisson distribution, where:

p (x = n) = e ^ (- l) * l ^ (x) / x!

Where he would come being the number of birds that there would be in 40 minutes, we know that in 2 hours, that is 120 minutes there are 13, therefore in 40 there would be:

l = 13 * 40/120

l = 4,333

Now, we have p (x> 3) and that is equal to:

p (x> 3) = 1 - p (x <= 3)

So, we calculate the probability from 0 to 3:

 p (x = 0) = 2.72 ^ (- 4.33) * 4.33 ^ (0) / 0! = 0.01313

p (x = 1) = 2.72 ^ (- 4.33) * 4.33 ^ (1) / 1! = 0.0568

p (x = 2) = 2.72 ^ (- 4.33) * 4.33 ^ (2) / 2! = 0.12310

p (x = 3) = 2.72 ^ (- 4.33) * 4.33 ^ (3) / 3! = 0.17767

If we add each one:

0.01313 + 0.0568 + 0.12310 + 0.17767 = 0.3707

replacing:

p (x> 3) = 1 - 0.3707

p (x> 3) = 0.6293

Which means that the probability is 62.93%

Answer:

Let's call the amount of 90% solution x.

We can write:

45% * 525 + 90%x = 55%(x + 525)

0.45 * 525 + 0.9x = 0.55(x + 525)

Solving for x we get x = 150 so the first blank is 150 and the second blank is 525 + 150 = 675.

Answer:

1/25

Step-by-step explanation:

5^-2

We know that a^ -b = 1/ a^b

5^-2 = 1/ 5^2

       = 1/25

Answer 1750000

Step-by-step explanation:

The number "one and three-quarter million" can be written in figures as 1,750,000.

Given the number one and three quarter million.

"One" represents the digit 1.

"Three-quarter" means three-fourths or 3/4.

In decimal form, this fraction is 0.75.

"Million" signifies a value of 1,000,000.

To represent this number in figures, we combine these components:

We start with the digit 1, representing "one."

Then we append the value 750,000, which corresponds to "three-quarter million."

Combining these two parts, we have 1,750,000.

Therefore, "one and three-quarter million" can be written in figures as 1,750,000.

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Find the given attachments

Answer:

Step-by-step explanation:Srry it's bit rough...

Answer:

The nearest whole is 122.99 repeated

Step-by-step explanation:

Answer:

The system has one solution.

Step-by-step explanation:

We have two equations:

y = -2x - 4

y = 3x + 3

Equalling them:

y = y

-2x - 4 = 3x + 3

5x = -7

[tex]x = -\frac{7}{5}[/tex]

And

[tex]y = 3x + 3 = 3(-\frac{7}{5}) + 3 = \frac{-21}{5} + 3 = \frac{-21}{5} + \frac{15}{5} = -\frac{6}{5}[/tex]

Replacing in the other equation we should get the same result.

[tex]y = -2x - 4 = -2(-\frac{7}{5}) - 4 = \frac{14}[5} - 4 = \frac{14}{4} - \frac{20}{5} = -\frac{6}{5}[/tex]

So the system has one solution.

Answer:

Option (2).

Step-by-step explanation:

From the figure attached,

EFGH is a quadrilateral and FH is line which divides the quadrilateral into two right triangles, ΔFEH and ΔHGF.

In ΔFEH and ΔHGF,

Sides EH ≅ FG [Given]

FH ≅ FH [reflexive property]

ΔFEH ≅ ΔHGF [HL (Hypotenuse - length) postulate of congruence]

Option (2) will be the answer.

Answer:

(C) 10

Step-by-step explanation:

x+y−z=8

Subtract y from both sides

x-z= -y+8

Add z to both sides

x= -y+z+8

Subtract 8 from both sides

x-8= -y+z

x−y+z=12

Add y to both sides

x+z=12+y

Subtract z from both sides

x=y-z+12

Subtract 12 from both sides

x-12=y-z

Multiply both sides by -1

-x+12= -y+z

Combine equations:

x-8= -x+12

Add x to both sides

2x-8+12

Add 8 to both sides

2x=20

Divide both sides by 2

x=10

The answer is (C) 10.

Answer:

meh

Step-by-step explanation:

Answer:

The annual interest tax shield to Salinas Corp would be of $560,000

Step-by-step explanation:

In order to calculate the annual interest tax shield to Salinas Corp if it goes through with the debt issuance we would have to calculate the following formula:

Annual Interest tax shield = Interest * tax

Interest = debt *rate of interest

Interest=$20 million * 0.07

Interest= $ 1.40 million

tax= 40%

Therefore, Annual Interest tax shield =$1.40 million * 0.40

Annual Interest tax shield = $560,000

The annual interest tax shield to Salinas Corp would be of $560,000

Answer:

32799000 cubic units

Step-by-step Explanation:

Height if the Pyramid=130 Units

Side Length of square base=870 Units

Volume of a Pyramid=[tex]\frac{1}{3}[/tex]* Base Area*Height

Since the base is a square,

Area of a Square of side length s[tex]=s^2[/tex]

Therefore:

Volume[tex]=\frac{1}{3}*870^2*130[/tex]

=32799000 cubic units

The volume of your pyramid is 32799000 cubic units.

Answer:

V = 3.28x10⁷

Step-by-step explanation:

The volume of a pyramid is given by:

[tex] V = \frac{1}{3}bh [/tex]

Where:

b: is the base of the pyramid  

h: is the height of the pyramid = 130            

The base of the square base of the pyramid is given by:

[tex] b = s^{2} [/tex]

Where:

s: is the side of the square base = 870

Thus, the base of the square base of the pyramid is:

[tex] b = s^{2} = (870)^{2} = 7.56 \cdot 10^{5} [/tex]  

Now, the volume of a pyramid is:

[tex] V = \frac{1}{3}bh = \frac{1}{3}(7.56 \cdot 10^{5})*130 = 3.28 \cdot 10^{7} [/tex]

Therefore, the volume of the pyramid is 3.28x10⁷.

I hope it helps you!

Answer:

[tex]68.04-1.959\frac{35.74}{\sqrt{250}}=63.618[/tex]    

[tex]68.04+1.959\frac{35.74}{\sqrt{250}}=72.461[/tex]    

And the best option for this case would be

Step-by-step explanation:

Information given

[tex]\bar X=68.04[/tex] represent the sample mean

[tex]\mu[/tex] population mean

s=35.74 represent the sample standard deviation

n=250 represent the sample size  

Confidence interval

The confidence interval for the mean is given by the following formula:

[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex]   (1)

The degrees of freedom are given by:

[tex]df=n-1=250-1=249[/tex]

The Confidence level is 0.95 or 95%, and the significance [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and the critical value for this case woud be [tex]t_{\alpha/2}=1.956[/tex]

And replacing we got:

[tex]68.04-1.959\frac{35.74}{\sqrt{250}}=63.618[/tex]    

[tex]68.04+1.959\frac{35.74}{\sqrt{250}}=72.461[/tex]    

And the best option for this case would be

Answer:

A. 1.8 ×[tex]10^{30}[/tex] Kg

B i. 3.0 × [tex]10^{17}[/tex] seconds

  ii. 9.6 × [tex]10^{9}[/tex] years

C. After 9.2 × [tex]10^{9}[/tex] (9.2 billion) years

Step-by-step explanation:

Given that the mass of the Sun = 2× [tex]10^{30}[/tex] Kg.

Mass of hydrogen when Sun was formed = 76% of 2× [tex]10^{30}[/tex] Kg

                            = [tex]\frac{76}{100}[/tex]  ×2× [tex]10^{30}[/tex] Kg

                           = 1.52 × [tex]10^{30}[/tex] Kg

Mass of hydrogen available for fusion = 12% of 1.52 × [tex]10^{30}[/tex] Kg

                           = [tex]\frac{12}{100}[/tex] × 1.52 × [tex]10^{30}[/tex] Kg

                           = 1.824 ×[tex]10^{30}[/tex] Kg

A. Total mass of hydrogen available for fusion over the lifetime of the sun is 1.8 ×[tex]10^{30}[/tex] Kg.

B. Given that the Sun fuses 6 × [tex]10^{11}[/tex] Kg of hydrogen each second.

i. The Sun's initial hydrogen would last;

                                     [tex]\frac{1.8*10^{30} }{6*10^{11} }[/tex]

                                 = 3.04 × [tex]10^{17}[/tex] seconds

The Sun's hydrogen would last 3.0 × [tex]10^{17}[/tex] seconds

ii. Since there are 31536000 seconds in a year, then;

The Sun's initial hydrogen would last;

                                     [tex]\frac{3.04*10^{17} }{31536000}[/tex]

                                 = 9.640 × [tex]10^{9}[/tex] years

The Sun's hydrogen would last 9.6 × [tex]10^{9}[/tex] years.

C. Given that our solar system is now about 4.6 × [tex]10^{9}[/tex] years, then;

                               [tex]\frac{9.6*10^{9} }{4.6*10^{9} }[/tex]

                             = 2.09

So that;   2 × 4.6 × [tex]10^{9}[/tex] = 9.2 × [tex]10^{9}[/tex] years

Therefore, we need to worry about the Sun running out of hydrogen for fusion after 9.2 × [tex]10^{9}[/tex] years.

Part(A): The total mass of hydrogen available 9.6 billion years.

Part(B): The total time is 5.10 billion years.

Part(D): The hydrogen will last [tex]5.04\times 10^9 \ years[/tex]

Our sun is the largest object in our solar system. The mass of the sun is approximately [tex]1.988\times 1030[/tex] kilograms

Part(A):

Given that,

The total mass of the Sun =[tex]2\times10^{30} kg[/tex]

Mass of hydrogen in Sun =  [tex]2\times10^{30} \times0.76\ kg[/tex]

The mass of hydrogen ever available for fusion is,

[tex]2\times10^{30} \times 0.76 \times 0.12 kg = 1.824\times 10^{29}[/tex]

Mass of hydrogen fuses each second = 600 billion kg/second.

Time hydrogen will last in seconds=[tex]1.824\times 10^{29}seconds.[/tex]

[tex]= 0.00304\times 10^{29 }= 3.04\times 10^{17}.[/tex]

Time hydrogen will last in seconds =[tex]1 year = 31,536,000 seconds.[/tex]

[tex]31,536,000 x = 3.04\times 10^{17} = 9.6 \ billion \ years.[/tex]

(B) Present age of sun = [tex]9.6-4.5 \ billion \ years[/tex]

The time when we need to worry about Sun running out of hydrogen for fusion = 5.10 billion years.

(D) The solar system is 4.6 billion years old that is [tex]4.6\times 10^9\ years[/tex]

And in part (B) we have calculated that hydrogen will last [tex]9.64\times 10^9[/tex] then,

[tex]9.64\times 10^9-4.6\times 10^9=5.04\times 10^9[/tex]

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Answer:

Number of people that can be served 7 ladles = 100 people

Step-by-step explanation:

We are told that;

Initial number of ladles proposed per person = 5

Number of persons to be fed based on 5 ladles = 140 persons

Thus, amount of ladles based on that data is;

140 people x 5 ladle/1 person = 700 ladles full of soup

Now, since the cook decides to give 7 ladles full of soup to each person, the number of people that can be fed will now be;

700 ladles ÷ 7 ladles/person = 100 persons

Answer:

At least 18 of the households have between 2 and 6 televisions.

Step-by-step explanation:

Chebyshev Theorem

The Chebyshev Theorem can also be applied to non-normal distribution. It states that:

At least 75% of the measures are within 2 standard deviations of the mean.

At least 89% of the measures are within 3 standard deviations of the mean.

An in general terms, the percentage of measures within k standard deviations of the mean is given by [tex]100(1 - \frac{1}{k^{2}})[/tex].

In this question:

Mean = 4

Standard deviation = 1

Percentage of households that have between 2 and 6 televisions.

2 = 4 - 2*1

So 2 is two standard deviations below the mean

6 = 4 + 2*1

So 6 is two standard deviations above the mean

By Chebyshev's Theorem, at least 75% of the measures are within 2 standard deviations of the mean.

Out of 24

0.75*24 = 18

At least 18 of the households have between 2 and 6 televisions.

Answer:

G

Step-by-step explanation:

Point G is coplanar with points B, C, H.

Answer:

The percentage of the students who completed the poll preferred rock and roll music.

P(RR) = 0.1423 = 14.23 %

Step-by-step explanation:

Explanation:-

Given total number of students n(S) = 1960

Given the Students at a high school were polled to determine the type of music they preferred.

Rap 916

Alternative 46

Rock and Roll 279

Country 183

Jazz 32

Other 89

Let ' RR' be the event of Rock and Roll preferred music

given Rock and Roll = 279

n( RR) =  279

The percentage of the students who completed the poll preferred rock and roll music.

[tex]P(RR) = \frac{n(RR)}{n(s)} = \frac{279}{1960}[/tex]

P(RR) = 0.1423 = 14.23 %