第 5 个问题 a multiple choice exam has 10 questions. each question has 3 possible answers, of which one is correct. a student knows the correct answers to 4 questions and guesses the answers to the other 6 questions. it turns out that the student answered the first question correctly. what are the chances that the student was merely guessing?

Answers

Answer 1

The chances that the student was merely guessing is 1/3.

Bayes Theorem determines the conditional probability of an event A given that event B has already occurred.

denoted by

[tex]P(A/B)=\frac{P(A)*P(B/A)}{P(B)}[/tex]

let A be the  event that the student knows the answer .

B be  the  event that the student does not knows the answer .

and

E be the event he gets answer correct .

According to the given question

[tex]P(A)=\frac{4}{10} \\\\ P(B)=1-\frac{4}{10} =\frac{6}{10}[/tex]

Probability that the answer is correct ,given that he knows the answer is

[tex]P(E/A)=1[/tex]

Probability that the answer is correct ,given that he guesses it is

[tex]P(E/B)=\frac{1}{3}[/tex]   [as the MCQ has 3 options and only one is correct]

We need to find the probability that he guesses the answer given that it is correct.

Required probability [tex]P(B/E)=\frac{P(B)*P(E/B)}{P(A)*P(E/A)+P(B)*P(E/B)}[/tex]

Substituting the values we get

[tex]P(B/E)=\frac{\frac{6}{10} *\frac{1}{3} }{\frac{4}{10} *1+\frac{6}{10} *\frac{1}{3} }[/tex]

[tex]=\frac{6}{30}*\frac{30}{18} \\ \\ =\frac{6}{18} \\ \\ =\frac{1}{3}[/tex]

Therefore ,  the chances that the student was merely guessing is 1/3.

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Related Questions

Cool Down: Drawing a Pool
A rectangular swimming pool measures 30 meters in length and 15 meters in width.
1. Make a scale drawing of the swimming pool where 1 centimeter represents 5 meters
11-1
1=201

Answers

The pool's new dimensions will be 10cm by 5cm, where 1 centimeter equals 5 meters.

What do we mean by dimensions?The dimension of a mathematical space is defined informally in physics and mathematics as the smallest number of coordinates required to specify any point within it. A line has a dimension of one because it only requires one coordinate to specify a point on it, such as the point at 5 on a number line.

So, scaling is a technique for resizing an object. It can either enlarge or decrease the size of the object.

A rectangular pool's dimensions of 50m by 25m

Making a scale drawing of the pool in which 1cm equals 5 meters, that is:

1 cm = 5m .... (1)

The length:

L = 50 m ..... (2)

Subtraction of both expressions 1 and 2:

1/L = 5/505L = 50L = 50/5L = 10cm

In terms of width:

The original width was 25 meters.

Obtain new width:

1/W = 5/255W = 25W = 25/5W = 5cm

Therefore, the pool's new dimensions will be 10cm by 5cm, where 1 centimeter equals 5 meters.

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The correct question is given below;
A rectangular swimming pool measures 50 meters in length and 25 meters in width. Make a scale drawing of the swimming pool where 1 centimeter represents 5 meters.

simplfy 4x2 - 3 x + 11 - 2x

Answers

Answer:

4x^2−5x+11

Step-by-step explanation:

combine like terms

What are 3 items that need to be addressed in the coding quality plan that will help achieve the kpi of 98 ccuracy?

Answers

Quality auditsCoder mentoringCoding support

are the three items that need to be addressed in the coding quality plan that will help achieve the KPI of 98 accuracy.

KPI:

KPI = Key Performance Indicator

A performance indicator or key performance indicator is a type of performance measurement. It basically evaluate the success of an organization or of a particular activity in which it engages.

Given,

Here we need to find the 3 items that need to be addressed in the coding quality plan that will help achieve the KPI of 98 accuracy.

The following are the 3 major pillars that are helps to achieve the KPI of 98 accuracy.

Quality auditsCoder mentoringCoding support

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25-(3x+10) the sum tear and share

Answers

Answer:

The Answer is -3x+15

Answer:

Step-by-step explanation:

25= (3x+10)

25-10 =

15=3x

15/3= 3x/3

5=x

I need help quickly,.............

Answers

The answer is -√125

Step-by-step explanation:

-√125 does not simplify to an integer as -√125 = -5√5

Andre performs a 90-degree counterclockwise rotation of polygon p and gets polygon p but he does not say what center of the rotation is

Answers

The center of rotation for the polygon p is shown as the red point in the attached graph below.

A plane figure spins around a point known as the center of rotation. Throughout the rotation, this point remains stationary.

The fixed point that the rotation revolves around in a figure or object with rotational symmetry is referred to as the center of rotation. As an illustration, we consider the point in the middle of a windmill where the blades start to rotate.A rotation is a transformation in which every point of a figure is turned through a predetermined angle and in a predetermined direction around a fixed point. The fixed point is referred to as the rotational center. The term "angle of rotation" refers to the rotation's amount and is expressed in degrees.

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please help am stuck​ ASAP

Answers

Answer:

linear

Step-by-step explanation:

y is always 1 behind x

PLEASE HELP ITS URGENT

Answers

Answer:

Hi, it's 8^9

Step-by-step explanation:

[tex]8^5\cdot \:8^4\\8^5\cdot \:8^4=8^{5+4}\\8^{5+4}\\=8^9\\[/tex]

Find an equation for the surface obtained by rotating the line x = 4y about the x-axis.

Answers

The equation: [tex]\frac{x^{2}}{6^{2}}={y^{2}+z^{2}[/tex],  represents a circle with radius r = y = x/6, and the surface that results is a cone, as obtained with the help of surface of revolution.

What is surface of revolution?A surface created by rotating a two-dimensional curve about an axis is known as a surface of revolution. As a result, the final surface is always symmetric along the azimuth.

Now,

If we consider the point (6y, y, 0) in the xy plane, it appears to be a circular path that is a cone when the curve is rotated about the x axis. The cone's equation takes the following form:

[tex]\frac{x^{2}}{c^{2}}=\frac{y^{2}}{a^{2}}+\frac{z^{2}}{b^{2}}[/tex]

Given that x = 6y, we square x = 6y to give the equation the form shown above, which results in:

x² = (6y)²

x² = 36y²

Circular paths go parallel to the y-axis, hence the equation should be circular in nature. 36z² needs to be added, so:

x² = 36y² + 36z²

=> [tex]\frac{x^{2}}{6^{2}}={y^{2}+z^{2}[/tex]

Hence, This equation represents a circle with radius r = y = x/6, and the surface that results is a cone, as obtained with the help of surface of revolution.

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Camille rolls two number cubes​ together, and records the sum. if she does this 180​ times, how many times should she expect the sum to be​ 7? explain your answer. loading... click the icon to view the possible sums of the number cubes. question content area bottom part 1 the sum should be 7 approximately enter your response here ​time(s). the probability of a sum of 7 is enter your response here. ​so, to predict the number of times that a sum of 7 is​ rolled, solve the proportion ▼ one sixth equals startfraction x over 36 endfraction . one sixth equals startfraction x over 180 endfraction . seven twelfths equals startfraction x over 180 endfraction . seven twelfths equals startfraction x over 36 endfraction .

Answers

The total number of times 7 can occur as the sum on rolling two cubes for 180 times is 30. It is gained by applying the knowledge of probability to the given problem.

What is probability?

Probability depicts the number of possibilities of how many times an event can occur. The probability of happening of an event invariably lies between 0 and 1. For a sure event, it is always 1. Its formula is given as P(E) = No. of favourable outcomes / Total no. of outcomes

Calculation of the total number of times 7 can appear as a sum on rolling two cubes for 180 times

Number of cubes rolled = 2

Total number of outcomes on rolling two cubes = 36

Total possibility of getting 7 as sum = 6

The probability of getting 7 as a sum on rolling two dice only once is given by P(E1)

P(E1) = 6 / 36

         = 1 / 6

She repeated the process 180 times  so the needed probability, P(E) is obtained by multiplying 180 by P(E1)

P(E) = 180 × (1 / 6)

P(E) = 30

Hence, the required probability of getting 7 as the sum is given by 30.

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The average temperature in the mountains is 62° in April. The average temperature in that same spot is −4° in December. Determine how much warmer this location is in April than in December, and determine which temperature is the farthest away from 0°.

Answers

Answer:

62-4=58

April is 58 much warmer than December and 62 is the farthest from 0

Answer:

I Can only tell you the temperature part, sorry...

Step-by-step explanation:

Basically 62 is actually farther away, and essay writers stink

I'm a bumblebee who likes to eat KFC - Ash the Fox

how to rewrite the function to determine whether it represents exponential growth or exponential decay

Answers

Answer: look at the screenshot

a pencil at a stationery store costs $1, and a pen costs $1.50. stella spent $21 at the store. she bought a total of 18 items. which system of equations can be used to find the number of pencils (x) and pens (y) she bought?

Answers

Answer:x+1.5y=21

Step-by-step explanation:

We know that a pencil is $1, so let's represent that as 1x or just x. We also know that each pen costs $1.50, and let's represent this as 1.5y for the number of pens Stella bought. Your equation would be x+1.5y=21.

The enrollment of a community college last
year was 4500 students. It increased by 5%
this year. What is the enrollment this year at
the community college?

Answers

Answer:

4725 Students

Step-by-step explanation:

First, multiply 4500 by 0.05 (which is 5% in decimal format.) You should get 225. Next, add 225 to the original value of 4500; you should get the answer, which is 4725 :)

Answer:

4725 Students

Step-by-step explanation:

To find the total enrollment of the community college this year, all we have to do is add the previous year's enrollment to 5% of the same value.

So...

Previous enrollment: 4500

5% of Previous enrollment = 0.05 * 4500 = 225

This year's enrollment = 4500 + 225 = 4725

So the final answer is 4725 students.

The probability that john,beth, and avery will be elected secretary of the key club are 1/8,2/5, and 1/3 what is the probability that one of the three will be elected?

Answers

the probability that one of the three will be elected = [tex]\frac{19}{30}[/tex]

Probability refers to potential. A random event's occurrence is the subject of this area of mathematics. The range of the value is 0 to 1. Mathematics has included probability to forecast the likelihood of certain events. The degree to which something is likely to happen is basically what probability means. You will understand the potential outcomes for a random experiment using this fundamental theory of probability, which is also applied to the probability distribution. Knowing the total number of outcomes is necessary before we can calculate the likelihood that a certain event will occur.

As per the question, it is given that :

Probability of John (A) = [tex]\frac{1}{8}[/tex]

Probability of Beth (B) = [tex]\frac{2}{5}[/tex]

Probability of Avery (C) = [tex]\frac{1}{3}[/tex]

The probability that one of the three will be elected :

P(A) * P(B') * P(C') + P(A') * P(B) * P(C') + P(A') * P(B') * P(C) = P(A) * (1 - P(B)) * (1 - P(C)) + (1 - P(A)) * P(B) * (1 - P(C)) + (1 - P(A)) * (1 - P(B)) * P(C).

here, P(A) = Probability of A happening

        P(A') = Probability of A not happening

= [tex](\frac{1}{8} * \frac{3}{5} * \frac{2}{3}) + (\frac{7}{8} * \frac{2}{5} * \frac{2}{3}) + (\frac{7}{8} * \frac{3}{5} * \frac{1}{3})[/tex]

= [tex]\frac{1}{20} + \frac{7}{30} + \frac{7}{20}[/tex]

= [tex]\frac{3 + 14 + 21}{60}[/tex]

= [tex]\frac{38}{60}[/tex]  =  [tex]\frac{19}{30}[/tex]

Therefore, the probability that one of the three will be elected = [tex]\frac{19}{30}[/tex]

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Suppose there is a 1.1°F drop in temperature for every thousand feet that an airplane climbs into the sky. If the temperature on the ground is 59.7°F, what will be the temperature at an altitude of 11,000 feet?

Answers

The temperature at an altitude of 11,000 feet will be 47.6°F

Calculating temperature

From the question, we are to calculate the temperature at an altitude of 11,000 feet

From the given information,

There is a 1.1°F drop in temperature for every thousand feet

and

The temperature on the ground is 59.7°F

Now,

We are to determine the temperature at an altitude of 11,000 feet

Since the temperature  drops by 1.1°F for every thousand feet,

Then,

At an altitude of 11,000 feet, the temperature would have dropped by 1.1°F 11000/1000 times

That is, the temperature would have dropped by that magnitude 11 times

Thus,

The temperature at an altitude of 11,000 feet = 59.7°F - 11×1.1°F

The temperature at an altitude of 11,000 feet = 59.7°F - 12.1°F

The temperature at an altitude of 11,000 feet = 47.6°F

Hence, the temperature at an altitude of 11,000 feet will be 47.6°F

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Sofias bank account statement said she had -25$ she dopsited 47$ Into her account what is Sofias balance after she made that deposite

Answers

Answer: $22

Step-by-step explanation:

47- 25= 22

Try It!
Evaluate.
a. √27

Answers

Answer:

The root of 27 would be 5.196

Step-by-step explanation:

solve the equation 2/3x+5=3

Answers

Answer:

x = -3

Step-by-step explanation:

Answer:

x=-3

Step-by-step explanation:

using the following quantities, calculated from these data, estimate the correlation between the percentage of dopamine receptors blocked and subjects’ ratings of the cocaine high. provide a standard error with your estimate. sum of products: 957.5 sum of squares (receptors blocked): 8145.441 sum of squares (rating of high): 372.5

Answers

correlation coefficient,r = 0.5497

Standard Error,[tex]SE_{r} = 0.1477[/tex]

What is dopamine?

Dopamine, also known as DA or 3,4-dihydroxyphenethylamine, is a neuromodulatory chemical with a variety of crucial functions in cells. It is an organic substance that belongs to the phenethylamine and catecholamine families. About 80% of the catecholamines in the brain are made up of dopamine. It is an amine produced by removing a carboxyl group from a molecule of L-DOPA, which is used as a precursor and is produced in the kidneys and brain. Plants and the majority of animals can produce dopamine as well. Dopamine performs the role of a neurotransmitter in the brain, which is a substance secreted by neurons (nerve cells) to communicate with other nerve cells. Although neurotransmitters are only produced in some parts of the brain, they have a systemic impact on numerous areas.

Let the random variable, X = % of dopamine receptors blocked and Y= subject's ratings of cocaine high.

The correlation coefficient, r

Given:

[tex]SS_{XY}[/tex] = 957.5

[tex]SS_{X}[/tex] = 8145.441

[tex]SS_{Y}[/tex]= 372.5

The correlation coefficient between the variables, X and Y is obtained using the following formula,

[tex]r=\frac{SS_{XY} }{\sqrt{SS_{X} \times SS_{Y} } }[/tex]

[tex]r=\frac{957.5 }{\sqrt{{8145.441} \times372.5 } } }[/tex]

r = 0.5497

The standard error for the estimate of the correlation coefficient is obtained using the following formula,

[tex]SE_{r} = \sqrt{\frac{1-r^{2} }{n-2} }[/tex]

From the scatterplot, the sample size, n = 34

[tex]SE_{r} = \sqrt{\frac{1-(0.5497)^{2} }{34-2} }[/tex]

[tex]SE_{r}=0.1477[/tex]

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A triangle with vertices at (-6, 5), (-5, 1), and (-8, 2) is reflected over the y-axis. What are the coordinates of the vertices of the reflected image? Enter the correct answers in the boxes. Show Hints Preimage coordinates Image coordinates (-6,5) (-5,1) (-8,2)​

Answers

The coordinates of the vertices of the reflected image are

A' ( 6,5) , B' ( 5,1), C' ( 8,2)

given that

a triangle has vertices A ( -6,5 ) , B (-5, 1) , C( -8,2 )

it is reflected over Y axis

we have to find the coordinates of the vertices of the reflected image

since it is reflected over Y axis then only the sign of x coordinates changes

the rule for a reflection over the Y axis is (x, y) -> ( -x , y)

the y coordinate in this case is unchanged

the vertices changes and it become

A( -6, 5) -> A' ( 6,5)

B ( -5, 1) -> B' ( 5,1)

C ( -8,2) -> C' ( 8,2)

preimage of coordinates attached below

Hence the coordinates of the vertices of the reflected image are

A' ( 6,5) , B' ( 5,1), C' ( 8,2)

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The students at Emir's school voted for a new school color. 738 students voted for orange and the other 82 students voted for yellow. What percentage of the students voted for yellow?

Answers

We can conclude that 10 percentage of the students voted for yellow.

What do we mean by percentage?A percentage is a number or ratio expressed as a fraction of 100 in mathematics. The percent sign, "%," is commonly used, but the abbreviations "pct.", "pct," and sometimes "pc" is also used. A percentage is a number with no dimensions; it has no unit of measurement.

Total number of students = 738 + 82 = 820

As we can notice that total number is 820 and the number of students that voted for yellow is 82.

So, 82/820 = 10%

Therefore, we can conclude that 10 percentage of students voted for yellow.

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If x= -2 , calculate the value of x squared - x

Answers

Answer:

x= -2

Step-by-step explanation:

A square number is the result when a number has been multiplied by itself

A transformation maps shape A onto shape B.

Each of the side lengths of shape B is four times as long as the corresponding side length of shape A.

Fill in the gaps to describe this transformation.

Answers

Answer: Enlargement with a scale factor 4

Step-by-step explanation:

      Since shape B is four times as long as shape A, this is an enlargement with a scale factor of 4.

      What is scale factor?

Scale factor is a ratio between the original and transformed objects. Here, it is 4.

Heellppp I cant figure it out

Answers

Answer:

It will be 29/1000

Step-by-step explanation:

Because each kg equal 1000 milie gram

the answer should be 29/1000. Because each kg equals 1000 millagrams

A jar of 60 coins contains 12 pennies. What percent of the coins are pennies?

Answers

[tex]\%( \alpha ) = \frac{cardinality( \alpha )}{cardinality( \omega) } \times 100 \\ [/tex]

[tex]\%(pennies) = \frac{12}{60} \times 100[/tex]

[tex]\%(pennies) = \frac{1}{5} \times 100 = \frac{100}{5} = 20 \% \\ [/tex]

Answer:

20%

Step-by-step explanation:

Simplify 2x (3x + 4) - (3x ² + 8x - 2)

Answers

Answer:

I think it’s 6x^3 + 16x^2 - 4x

After simplify of this equation 2x (3x + 4) - (3x ² + 8x - 2). We get, the two factors which are +√(-2/3), -√(-2/3).

Given Equation:

2x (3x + 4) - (3x ² + 8x - 2)

2x (3x + 4) - 3x ² - 8x + 2

6x² + 8x - 3x ² - 8x + 2

3x ² + 2

To find the factors

3x ² + 2 = 0

x ² = -2/3

x = ±√(-2/3).

Therefore, the factors of given equation are +√(-2/3), -√(-2/3).

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4. jamaal is collecting data on freddie's on-task behavior. he looks to see if freddie is on-task for an entire 10-second interval. if he is, he marks yes. if freddie looks around during the 10 seconds, he marks no. what type of data recording is jamaal using?

Answers

Jamaal using whole interval type of data recording to collect the data on Freddie’s on-task behavior.

What do you mean by whole interval data collection?

One form of interval recording technique is whole interval recording. An interval recording approach involves watching to see if a behavior happens or not within predetermined intervals of time. After determining the duration of an observation session, the time is divided into shorter segments that are all of the same length. To record the incidence of behavior, ten boxes may be utilized to divide a 10-minute observational session into 1-minute intervals. A whole interval recorder uses a X for occurrence and a O for no non-occurrence to indicate if a behavior occurred during the entire interval.

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Four bags were divided equally among 5 people how much of a bag did each get? how??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

Answers

Answer:

Each person would get 80% of a bag

Need help please quick asap thank you giving brainlest

Answers

Answer C :

[tex](5 {}^{ - 3} ) {}^{6} = 5 {}^{ - 3 \times 6} = 5 {}^{ - 18} = \frac{1}{5 {}^{18} } [/tex]

Answer:

C is correct.

Step-by-step explanation:

(5^-3)^6

= 5 ^(-3*6)

= 5^-18

= 1 /5^18.

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