There are 5 questions on a multiple choice exam, each with five possible answers. If a student guesses on all five questions, what is the probability the student gets two questions correct? Express your answer as a percent rounded to the nearest tenth.

3.8%

18.7%

20.5%

16.9%

Answers

Answer 1

Answer:

[tex]20.5\%[/tex]

Step-by-step explanation:

Let's write out a case for two specific questions being correct and the rest being incorrect:

[tex]\frac{1}{5}\cdot \frac{1}{5}\cdot \frac{4}{5}\cdot \frac{4}{5}\cdot \frac{4}{5}[/tex],

The [tex]\frac{1}{5}[/tex] represents the chances of getting the question correct, as there are 5 answers and 1 correct answer choice.

The [tex]\frac{4}{5}[/tex] represents the chances of getting the question incorrect, as there are 5 answers and 4 incorrect answer choices.

The equation above does show the student getting two answers correct and three answers incorrect, but it only shows one possible case of doing so.

We can choose any two of the five questions to be the ones the student gets correct. Therefore, we need to multiply this equation by the number ways we can choose 2 from 5 (order doesn't matter): [tex]\binom{5}{2}=10[/tex].

Therefore, the probability the student gets two questions correct is:

[tex]\frac{1}{5}\cdot \frac{1}{5}\cdot \frac{4}{5}\cdot \frac{4}{5}\cdot \frac{4}{5}\cdot \binom{5}{2}=\frac{1}{5}\cdot \frac{1}{5}\cdot \frac{4}{5}\cdot \frac{4}{5}\cdot \frac{4}{5}\cdot 10=0.2048\approx \boxed{20.5\%}[/tex]


Related Questions

Suppose you have budgeted for 3 expenditures, $100, $150 and $50. However the amount that you have spent is $95, $175 and $20. Did you spend more or less than what was budgeted? By how much? (Show Your Work)

Answers

Answer:

Spent less than budget by $10

Step-by-step explanation:

→ Work out total budget

100 + 150 + 50 = 300

→ Work out total expenditure

95 + 175 + 20 = 290

Please help with this, will give brainliest.

Answers

Answer:

A)  4 cats

Step-by-step explanation:

let x = 16-y

substitute to get:

18(16-y) + 30y = 432

288 - 18y + 30y = 432

12y = 144

y = 12

x = 4

Anybody else panicking while trying to finish their classes?
(please say it's not just me)

Answers

Answer:

no it's me too haha

Step-by-step explanation:

yes currently i am taking my pre calc final and am definitely failing it

What is the common denominator of 1/a+1/b in the complex fraction ((1/a-1/b)/(1/a+1/b)? A^2b^2 a-b a+b ab

Answers

Answer:

D. ab

Step-by-step explanation:

1/a + 1/b = b / ab + a / ab = (b + a) / ab

The common denominator is ab

Correct choice is D

Answer:D

Step-by-step explanation:

10 points !
what is 20% of 30 ?

Answers

Answer:

6

Step-by-step explanation:

Of means multiply

20% * 30

Change to decimal form

.20 * 30

6

Answer:

6

Step-by-step explanation:

[tex]20\% \ of \ 30 = \frac{20}{100} \times 30 = \frac{1}{5} \times 30 = 6[/tex]

square OABC is drawn on a centimetre grid. O is (1,3) A is (3,3) B is (3,5)​

Answers

Answer:

you have to tell us the question honey

Karen can make 14 cakes in 6 hours. how many cakes can she make in 15 hours?

Answers

Answer:  35 cupcakes!

Step-by-step explanation:

Please help

1< |x– 2| < 5

Answers

Answer:

[tex]1 < |x -2|< 5\\1< |x-2| = |x-2| > 1\\-1 >x-2 \ , \ x-2<1\\1>x \ , \ x >3\\\\|x-2|<5 = -5 < x-2<5 = -3 <X<7\\\\Therefore , by \ merging \ overlapping \ intervals \\\\-3<x<1\quad \mathrm{or}\quad \:3<x<7[/tex]

For the equation y = 2x2 − 5x + 18, choose the correct application of the quadratic formula.

Answers

y= 2x^2 - 5x + 18 ? i don’t really know quadratic formula yet. but the answer might be that equation & x = 18




Jimmy and Jennifer are selling pies for a school fundraiser. Customers can buy apple pies and blackberry pies. Jimmy sold 10
apple pies and 2 blackberry pies for a total of $80. Jennifer sold 10 apple pies and 3 blackberry pies for a total of $100. Find the
cost each of one apple pie and one blackberry pie.

Answers

Answer:

One apple pie is $4 and one blackberry pie is $20

Step-by-step explanation:

Create a system of equations where a is the cost of one apple pie and b is the cost of one blackberry pie:

10a + 2b = 80

10a + 3b = 100

Solve by elimination by multiplying the top equation by -1, then adding the equations together:

-10a - 2b = -80

10a + 3b = 100

Add these together:

b = 20

So, one blackberry pie is $20. Plug in 20 as b into one of the equations, and solve for a:

10a + 2b = 80

10a + 2(20) = 80

10a + 40 = 80

10a = 40

a = 4

So, one apple pie is $4.

One apple pie is $4 and one blackberry pie is $20

Find the mean of this data set: 11, 13, 13, 11, 13

Answers

Answer:

I'm saososowowo3iwiqiwuwuwuwbabahaqbqnwnwnwnwnwnwnwnwnwnwnwnwnwnwnwnwnen

Answer:

I'mnot really sure if it might be correct but I believe it's 12.2 :))

determine the value of x.. i will give brainliest

Answers

Answer:

Step-by-step explanation:

8x-1+6x+13=180 degree(being co interior angle)

14x=180-12

x=168/14

x=12

Triangle JKL has the coordinates listed: J (5, -8), K (10, -8), L (7, -4) Where is J’ after a reflection over the y-axis?

Answers

Answer:

The Rule for reflection over the y-axis is given by (x,y) to (-x,y).

so, J' (-10,-8)

✐----------------------

hope it helps...

have a great day!

Answer:

J' Coordinates = (-5, -8)

Step-by-step explanation:

We know that in the coordinate point J (5, -8);

x-value = 5

y-value = -8

In order to reflect J over the y-axis, we will keep the y-value of the coordinate same and then reverse the x-value to it's opposite, Therefore the J' coordinates would be;

x-value = -5

y-value = -8

J' Coordinates = (-5, -8)

Hope this helps!

PLEASE HELP WILL GIVE BRAINLYIST!!!!!
Find the area of each figure.

Answers

Answer:

area of triangle=base*height/2

=4*5/2

=20/2

=10m^2

Step-by-step explanation:

Find the area of a circle with the radius of 73 feet

Answers

Answer:

Step-by-step explanation:

area of a circle=πr^2

=3.14*(73)^2

=3.14*5329

=16733.06 ft^2

Answer:

A = 5329 pi ft^2

If we approximate pi with 3.14

A = 3.14*5329=16733.06 ft^2

If we use the pi button

A =16741.54725 ft^2

Step-by-step explanation:

The area of a circle is given by

A = pi r^2

The radius is 73

A = pi ( 73) ^2

A = 5329 pi ft^2

If we approximate pi with 3.14

A = 3.14*5329=16733.06 ft^2

If we use the pi button

A =16741.54725 ft^2

The probability for event A is 0.4, the probability for event B is 0.2, and the probability of events A and B is 0.1.

Why are the events not independent?

The sum of P(A) and P(B) is greater than P(A and B).
The product of P(A) and P(B) is greater than P(A and B).
The product of P(A) and P(B) is not equal to P(A and B).
The sum of P(A) and P(B) is not equal to P(A and B)

Answers

Answer:

the correct answer is the product of PA) and P(B) is not equal to P(A and B)

hmm need help please

Answers

Answer:

Hello! answer: b = 5

Step-by-step explanation:

13 × 13 = 169 12 × 12 = 144 169 - 144 = 25 5 × 5 = 25 therefore b = 5 hope that helps!

12x12=144

13x13=169

169-144=25

5^2= 25

B=5 feet

Pls solve I will mark brainliest

Answers

Answer:

292.5

Step-by-step explanation:

1/2*13(20cm+25cm)

Please help me for my cousin

Answers

all you have to do is plot the points to the corresponding numbers. for example, for the scorpions the number 55 is repeated three times so in the number line for the scorpions you’ll put 3 dots above the number 55

Which expression is equivalent to (3x + 4)(2x - 3)?

Answers

Answer:

Step-by-step explanation:

If there are choices, you should list them. It's a guess about which is correct. I'll list 2 of them.

(3x + 4)(2x - 3) can be

(2x - 3)(3x + 4) or

F: 3x*2x = 6x^2

O:3x * -3 = - 9x

I : 4 * 2x = 8x

L: 4 * - 3 = - 12

When added, you get

6x^2 -9x + 8x - 12

6x^2 - x - 12

Assume the selling price of your house calculate the
commission amount of your house if the commission rate
is 5•/•​

Answers

Answer:

$14000

Step-by-step explanation:

Given that :

Commission 5% of sale price

Sale price of house = $280,000

Commission = 5% of $280,000

Hence,

Commission = 0.05 * $280,000

Commission = $14,000

Please help?!?!


Thanjss

Answers

Answer:

Step-by-step explanation:

y= mx+ b helps you find the equations of the lines

y= x+2 is the line with slope m=1, and y-intercept b=2

y= -4x-3 is the line with slope m=-4, and y-intercept b=-3

y > x+2 because is a dotted line

y ≤ -4x-3 because is a solid line

Answer:

aha i see yo bbg

Step-by-step explanation:

(lipbite)

Find the volume of the cylinder when its height is 13 ft, and its radius is 12
ft. Round to the nearest tenth."

Answers

I think it’s 5878.08


V = pi * r^2 * h
= 3.14 * 12^2 * 13
= 3.14* 144 * 13
= 5878.08

Use the given area A of the rectangle to find the value of x . A rectangle with its length labeled left-parenthesis 4 x plus 3 right-parenthesis feet and width labeled left-parenthesis 4 x minus 5 right-parenthesis feet. The area of the rectangle is 209 square feet.

Answers

Answer:

x = 4

Step-by-step explanation:

Length = (4x + 3) feet

Width = (4x - 5 )feet  

Area = Length x Breadth

209 = (4x + 3)(4x - 5)

209 = 4x( 4x -5) + 3 (4x -5)

[tex]209 = 16x^2 -20x +12x -15\\\\0 = 16x^2 -8x -15 -209\\\\16x^2 -8x -224 = 0[/tex]

[tex]Quadratic \ Equation \ with a = 16, b = -8, c = -224 \\\\x = \frac{-b \pm \sqrt{b^2 -4ac}}{2a}\\\\Substitute \ a, b, c \ in \ the \ equation.\\\\x = \frac{-b + \sqrt{b^2 -4ac}}{2a}, x =\frac{-b \ - \sqrt{b^2 -4ac}}{2a}\\\\x = \frac{8+ \sqrt{64 +14336}}{32}, x = \frac{8- \sqrt{64 +14336}}{32}\\\\x = \frac{8+ \sqrt{14400}}{32}, x = \frac{8-\sqrt{14400}}{32}\\\\x = \frac{8+120 }{32}, x= \frac{8-120}{32}\\\\x = \frac{128}{32} , x = \frac{-112}{32}\\\\x = 4 , x = \frac{-7}{2}[/tex]

Since measure of length or width cannot be negative, we take x = 4

help mee please its math

Answers

Answer:

m<D = 34

Step-by-step explanation:

Exterior angles thm:

3x - 2 + 68 = 9x - 6

3x + 66 = 9x - 6

3x - 9x = -6 - 66

-6x = -72

x = 12

<D:

3x - 2

3(12) - 2

36 - 2

34

PLEASE HELP DUE IN 5 MINUTES!! NO LINKS! HELP WITH THE FIRST ONE ONLY!

Answers

Answer:

PR=130, MPR=180, MRT=180, MT=130 HOPE THIS HELPED

Step-by-step explanation:

reduce 9/45 to simplest terms in fractions

Answers

Answer:

1/5

hope this helps

have a good day :)

Step-by-step explanation:

Answer:

1/5.

Step-by-step explanation:

Divide top and bottom of the fraction by 9.

Select all that are equivalent to 4/16
1/5
0.25
0.252525
25%

Answers

Answer:

0.25 and 25% are equivalent

Step-by-step explanation:

please help, I got 8 of these wrong already :(

Answers

Answer:

●{22,28,35} ○{5,12,13}○{25,70,74} ○{48,56,73}

The image below shows F with perpendicular tangent lines at points A and B.

Will be reported if you add something that does not match the question

Answers

Answer:

∠AFB= 90°  

∠ADB= 360-90

270Shape AFBC →is a Square because every angle is 90 degrees.

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

hope it helps...

have a great day!!

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