Richard has just been given an l0-question multiple-choice quiz in his history class. Each question has five answers, of which only one is correct, Since Richard has not attended a class recently, he doesn't know any of the answers, Assuming that Richard guesses on all 10 questions. Find the indicated probabilities.
A) What is the probability that he will answer all questions correctly?
B) What is the probability that he will answer all questions incorrectly?
C) What is the probability that he will answer at least one of the questions correctly?
Then use the fact that P(r1) = 1 P(r = 0).
D) What is the probability that Richard will answer at least half the questions correctly?

Answers

Answer 1

Answer:

a) 0.0000001024 probability that he will answer all questions correctly.

b) 0.1074 = 10.74% probability that he will answer all questions incorrectly

c) 0.8926 = 89.26% probability that he will answer at least one of the questions correctly.

d) 0.0328 = 3.28% probability that Richard will answer at least half the questions correctly

Step-by-step explanation:

For each question, there are only two possible outcomes. Either he answers it correctly, or he does not. The probability of answering a question correctly is independent of any other question. This means that 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.

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

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

Each question has five answers, of which only one is correct

This means that the probability of correctly answering a question guessing is [tex]p = \frac{1}{5} = 0.2[/tex]

10 questions.

This means that [tex]n = 10[/tex]

A) What is the probability that he will answer all questions correctly?

This is [tex]P(X = 10)[/tex]

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

[tex]P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} = 0.0000001024[/tex]

0.0000001024 probability that he will answer all questions correctly.

B) What is the probability that he will answer all questions incorrectly?

None correctly, so [tex]P(X = 0)[/tex]

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

[tex]P(X = 0) = C_{10,0}.(0.2)^{0}.(0.8)^{10} = 0.1074[/tex]

0.1074 = 10.74% probability that he will answer all questions incorrectly

C) What is the probability that he will answer at least one of the questions correctly?

This is

[tex]P(X \geq 1) = 1 - P(X = 0)[/tex]

Since [tex]P(X = 0) = 0.1074[/tex], from item b.

[tex]P(X \geq 1) = 1 - 0.1074 = 0.8926[/tex]

0.8926 = 89.26% probability that he will answer at least one of the questions correctly.

D) What is the probability that Richard will answer at least half the questions correctly?

This is

[tex]P(X \geq 5) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)[/tex]

In which

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

[tex]P(X = 5) = C_{10,5}.(0.2)^{5}.(0.8)^{5} = 0.0264[/tex]

[tex]P(X = 6) = C_{10,6}.(0.2)^{6}.(0.8)^{4} = 0.0055[/tex]

[tex]P(X = 7) = C_{10,7}.(0.2)^{7}.(0.8)^{3} = 0.0008[/tex]

[tex]P(X = 8) = C_{10,8}.(0.2)^{8}.(0.8)^{2} = 0.0001[/tex]

[tex]P(X = 9) = C_{10,9}.(0.2)^{9}.(0.8)^{1} \approx 0[/tex]

[tex]P(X = 10) = C_{10,10}.(0.2)^{10}.(0.8)^{0} \approx 0[/tex]

So

[tex]P(X \geq 5) = P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10) = 0.0264 + 0.0055 + 0.0008 + 0.0001 + 0 + 0 = 0.0328[/tex]

0.0328 = 3.28% probability that Richard will answer at least half the questions correctly


Related Questions

A certain company sends 50% of its overnight mail parcels via express mail service E1. Of these parcels, 1% arrive after the guaranteed delivery time (denote the event late delivery by L). Suppose that 10% of the overnight parcels are sent via express mail service E2 and the remaining 40% are sent via E3. Of those sent via E2 on 2% arrive late, whereas 5% of the parcels handled by E3 arrive late.
A. If a record of an overnight mailing is randomly selected from the company's file, what is the probability that the parcel went via El and was late?
B. What is the probability that a randomly selected parcel arrived late?
C. If a randomly selected parcel has arrived on time, what is the probability that is was not sent via E1?

Answers

Answer:

A. 0.005 = 0.5% probability that the parcel went via El and was late

B. 0.027 = 2.7% probability that a randomly selected parcel arrived late.

C. 0.8148 = 81.48% probability that is was not sent via E1

Step-by-step explanation:

Conditional Probability

We use the conditional probability formula to solve this question. It is

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

In which

P(B|A) is the probability of event B happening, given that A happened.

[tex]P(A \cap B)[/tex] is the probability of both A and B happening.

P(A) is the probability of A happening.

A. If a record of an overnight mailing is randomly selected from the company's file, what is the probability that the parcel went via El and was late?

50% are chosen via E1, and of those, 1% were late. So

[tex]p = 0.5*0.01 = 0.005[/tex]

0.005 = 0.5% probability that the parcel went via El and was late

B. What is the probability that a randomly selected parcel arrived late?

1% of 50%(via E1)

2% of 10%(via E2)

5% of 40%(via E3).

So

[tex]p = 0.01*0.5 + 0.02*0.1 + 0.05*0.4 = 0.027[/tex]

0.027 = 2.7% probability that a randomly selected parcel arrived late.

C. If a randomly selected parcel has arrived on time, what is the probability that is was not sent via E1?

Conditional Probability.

Event A: Late

Event B: Not sent via E1

0.027 = 2.7% probability that a randomly selected parcel arrived late, which means that [tex]P(A) = 0.027[/tex]

Late and not sent via E1:

2% of 10%(via E2)

5% of 40%(via E3).

So

[tex]P(A \cap B) = 0.02*0.1 + 0.05*0.4 = 0.022[/tex]

Desired probability:

[tex]P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.022}{0.027} = 0.8148[/tex]

0.8148 = 81.48% probability that is was not sent via E1

A triangle has an area of 37.5 inches the height of the triangle is 20 inches what is the length of the base of the triangle?​

Answers

Answer:

base = 3.75 inches

Step-by-step explanation:

37.5 = 20b/2

37.5 = 10b

b = 3.75

Help please some one

Answers

Answer:

i dont know im just doing this for the points

Use the equation below to find y, if m=6, x=4, and b= 15. y=mx-b​

Answers

Answer:

9

Step-by-step explanation:

Y = MX-B,

therefore Y = (6*4) - 15,

so Y = 24 - 15

Y = 9

The coordinate point F(-8, 0) after a dilation with scale factor of 0.25, centered at the origin, becomes the point
O (-2,0)
O (-2, 0.25)
O (2, 0.25)
O (2,0)​

Answers

Answer:

[tex](-2,\, 0)[/tex].

Step-by-step explanation:

Dilate a point [tex](x,\, y)[/tex] by a scale factor of [tex]r[/tex] with [tex](a,\, b)[/tex] as the center, and the resultant point would be at [tex](a + r\, (x - a),\, b + r\, (y - a))[/tex].

In this question:

Point to dilate: [tex](x,\, y) = (-8,\, 0)[/tex].

Scale factor: [tex]r = 0.25[/tex].

Center of dilation: [tex](a,\, b) = (0,\, 0)[/tex].

The resultant point would be:

[tex](0 + 0.25\, (-8 - 0),\, 0 + 0.25\, (0 - 0))[/tex], which simplifies to [tex](-2,\, 0)[/tex].

What type of transformation
has this figure made

Answers

Answer:

translation

Step-by-step explanation:

a rotation would make it horizontal which it is not

reflection would flip it its not fliped.

There for its translation

hope this helps

Transfer dish susu send

Question 3 (1 point)
If a ball has a density of 3 grams per cubic centimeter and a mass of 6.2 grams, what
is the volume of the ball? Round your answer to the nearest tenth.
I

Answers

Answer:

tydghhhhhhhhhhhhhhhhhhhhhhh

Step-by-step explanation:

hv

Answer:






Explanation:

Rotation 180° about the origin

Answers

Answer:

Step-by-step explanation:

to rotate about origin by 180 °  also means to  change ( x, y) ⇔( -x,-y)

the double arrows just mean to change into.. or "transform"  ( I think that there might have even been a movie about this,   called   "transformers" :D JK)

T=( -2, 1)

S = ( -4, 3)

R = ( -5, -2)

use the transform  ( x, y) ⇔( -x,-y)

T' = (2,-1)

S' = ( 4, -3 )

R' = (5 , 2 )

if you draw this on a piece of graph paper, you'll see it's the triangle spun 180 °  around the origin  :)

3) Suppose you deposit $10,000 in a savings account that pays interest at an annual rate of 5%
compounded quarterly. How many years will it take for the balance in your savings account to reach
$12,000?

Answers

9514 1404 393

Answer:

  3.67 years

Step-by-step explanation:

The amount is found using the compound interest formula.

  A = P(1 +r/n)^(nt)

for principal P invested at annual rate r compounded n times per year for t years.

We can solve this for t:

  A/P = (1 +r/n)^(nt) . . . . divide by P

  log(A/P) = (nt)log(1 +r/n) . . . . take the logarithm

  t = log(A/P)/(n·log(1 +r/n)) . . . . divide by the coefficient of t

Filling in the given values, we find ...

  t = log(12000/10000)/(4·log(1 +0.05/4)) ≈ 3.6692

It will take about 3.67 years for the balance to reach $12,000.

Answer:

the answer is 3.67 years

What is the measure of x? Please help!

Answers

Answer:

x =√[y²+(27)²] = √[ z² - 3² +(27)²]

Step-by-step explanation:

step 1) x=√[y²+(27)²]

step 2)

We find y

z²=y²+3² → y² = z² - 3²

step 3) x = √[ z² - 3² +(27)²]

In ABC, what is the value of x?

Answers

Answer:

122 po nya ta

Step-by-step explanation:

sana po makatulong

Answer:

70

Step-by-step explanation:

I got it wrong and this is what showed up

Determine the scientific notation for the number.
124,900,000,000

Answers

1.249 X 10^11
......

Answer: 1.249 × 10^11

Step-by-step explanation:

Here are two patterns made using identical rhombuses. Without using a protractor, determine the value of a and b. (Remember that all the way around a circle is 360°. Start by finding the measure of angle a in the figure on the left.)

Answers

Answer:

hope it helps

Step-by-step explanation:

have a great day

Triangle ABC has vertices A (6, 1), B (1,7), and C (-3, -2). The translation to create triangle A'B'C' is (x, y) + (x-1, y +2).

Which of the following will be the coordinates of the vertices of triangle A'B'C?

A (5,2), (0, -4), (0,9)
B (5,3), (0, -4), (0,8)
C (5,3), (0,9), (-4,0)
D (5,2), (1, -3), (0,9)​

Answers

Answer:

I think C is the answer

6. If a person adopts a pet, it's either a cat or a dog. 25% of the time, it's a cat and 75% of the time, it's a dog. If you meet someone at the shelter that adopted three pets, what's the probability that they got either: three cats or three dogs? Show your calculation and give your single answer as a decimal.

Answers

Answer:

0.0156 probability that they got three cats.

0.4219 probability that they got three dogs.

Step-by-step explanation:

For each person there are only two possible outcomes. Either they adopted a dog, or a cat. The probability of a person adopting a cat or a dog is independent of any other person, which means that the binomial probability distribution is used 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.

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

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

Three people:

This means that [tex]n = 3[/tex]

What's the probability that they got three cats?

25% of the time it's a cat adopted, which means that [tex]p = 0.25[/tex]

This is P(X = 3). So

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

[tex]P(X = 3) = C_{3,3}.(0.25)^{3}.(0.75)^{0} = 0.0156[/tex]

0.0156 probability that they got three cats.

What's the probability that they got three dogs?

75% of the time it's a dog adopted, which means that [tex]p = 0.75[/tex]

This is P(X = 3). So

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

[tex]P(X = 3) = C_{3,3}.(0.75)^{3}.(0.25)^{0} = 0.4219[/tex]

0.4219 probability that they got three dogs.

8th grade math, explain if you can please.

Answers

Answer:

I'm pretty sure that the answer is 1.76?

Step-by-step explanation:

The formula is this tho:

V=πr^2h

-8x + y = -16
-3x + y = -5​

Answers

Answer:

x= 11/3

y= 6

Step-by-step explanation:

-8x+y=-16

-3x+y = - 5

Multiply the second equation by -1, we get,

-8x + y = -16

3x -y = 5

--------------------

-3x = -11

x= 11/3

x=11/3. so,

-3×11/3 +y = -5

-11+y=-5

y= -5+11

y=6

can anyone help me with #1?

Answers

Answer:

x = 16.1 in

Step-by-step explanation:

Using sin law

sin44 / x = sin98/ 23in

x = 16.1 in (nearest tenth)

i need help with this one

Answers

Answer:

I

Step-by-step explanation:

The weekly amount of money spent on maintenance and repairs by a company was observed, over a long period of time, to be approximately normally distributed with mean $440 and standard deviation $10. How much should be budgeted for weekly repairs and maintenance so that the probability the budgeted amount will be exceeded in a given week is only 0.05

Answers

Answer:

$456.45 should be budgeted.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

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 p-value, we get the probability that the value of the measure is greater than X.

Mean $440 and standard deviation $10.

This means that [tex]\mu = 440, \sigma = 10[/tex]

How much should be budgeted for weekly repairs and maintenance so that the probability the budgeted amount will be exceeded in a given week is only 0.05?

This is x for which

P(X > x) = 0.05

So this is the 100 - 5 = 95th percentile, which is X when Z has a pvalue of 0.95, so X when Z = 1.645.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]1.645 = \frac{X - 440}{10}[/tex]

[tex]X - 440 = 10*1.645[/tex]

[tex]X = 456.45[/tex]

$456.45 should be budgeted.

The volume of a suitcase if 8,556 cubic inches. It is 32 inches long and 15.5 inches high. What is width of the suitcase?

Answers

Answer:

17.25

Step-by-step explanation:

8556 / 32 / 15.5 = 17.25

Determine the measures of the following; (SOMEONE PLS) :v

Answers

arc AC=27°

arc BD=33°

arc CB=120°

hope it helps you ❣❣

Mark me as brainliest

Gold is mined at Cortez Gold Mine in Nevada. For every ton of raw material dug out of the ground, you get one ounce of gold. Each truck hauls 394 tons, and each day, there are 1000 trucks that haul material out of the ground. Assuming the current price of gold to be $1,607 per ounce. How much money is made each day at Cortez Gold Mine

Answers

Answer:

[tex]\$633158000[/tex]

Step-by-step explanation:

[tex]1\ \text{ton of raw material}=1\ \text{ounce of gold}[/tex]

1 truck hauls 394 ton of raw material

[tex]1\ \text{truck}=394\ \text{ton of raw material}=394\ \text{ounce of gold}[/tex]

There are 1000 trucks so

[tex]1000\ \text{trucks}=394\times 1000=394000\ \text{ounce of gold}[/tex]

1 ounce of gold cost $1607

[tex]394000\ \text{ounce of gold}=394000\times 1607=\$633158000[/tex]

The amount of money made each day at Cortez Gold Mine is [tex]\$633158000[/tex].

find the area of this polygon - PLZZZZZ HELP I WILL GIVE 30 points T^T

Answers

Answer:

82 m should be correct i hope

Step-by-step explanation:

Cup G has a diameter of 4 in. and a height of 8 in. Find the volume of Cup G.

Answers

Answer:

32pi

Radius=1/2 Diameter

radius=2

Area of circle= pi*radius^2= 4pi

4pi*8=32 pi

v=(3.14)(2^2)(8)
(3.14)(32)
v=100.48

Find the perimeter of the triangle to the right

Answers

9514 1404 393

Answer:

  76.5 units

Step-by-step explanation:

This is an interesting question. The side lengths are proportional to the sine of the opposite angle. So, we can find a scale factor for the given length by adding the sines of the angles and dividing by the sine of the angle opposite the given side.

The three angles are ...

  43°, 63° and 74° (the supplement of the sum of the other two)

So, the scale factor mentioned above is ...

  (sin(43°) +sin(63°) +sin(74°))/sin(74°) ≈ 2.636396

Then the perimeter of the triangle is ...

  (2.636396)(29) ≈ 76.5 . . . units

I need help what's the answer anyone?​

Answers

Answer:

B

Step-by-step explanation:

15 Points, please give full equation on how you answer.

Answers

Maybe C i’m just an educated guess I’m very sorry if it’s wrong but I’m just trying to help

Solve for t: F =2t+k/3g

Answers

Answer:

[tex]F = \frac{2t + k}{3g} \\3Fg = 2t+k\\3Fg - k = 2t\\t = \frac{3Fg - k}{2}[/tex]

Calculator
13 in
94
7.5 in.
What is the area of this triangle?
Enter your answer as a decimal in the box. Round only your final
answer to the nearest tenth.

Answers

Answer:

9165.0

Step-by-step explanation:

13*94*7.5 = 9165.0

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