There are some red and blue balls in a bag of 21 balls and the probability of picking 2 red balls out in a row is 1/14 how many red balls are there?

Answers

Answer 1

Answer:

6 red balls

Step-by-step explanation:

The probability in the first pick

6/21

The probability in the second pick (without replacement)

5/20

the requested probability

(6/21)(5/20) = 30/420

simplification

30/420 = 3/42 = 1/14

Hope this helps

Answer 2

Answer:

6 red balls.

Step-by-step explanation:

If there are x red balls then

probability of 2 red balls

= x/21 * (x - 1)/20 = 1/14

x^2 - x / 420 = 1/14

x^2 - x = 30

x^2 - x - 30 = 0

(x - 6)(x + 5) = 0

x = 6.


Related Questions

What is the length of CB in ABC

Answers

There needs to be values to answer the question.

What amount of a 40% acid solution must be mixed with 200 mL 10% solution to produce a 20% solution?

Answers

Answer:

Step-by-step explanation:

(x + 200)20 = 200(10) + x(40)

20x + 4000 = 2000 + 40x

2000 = 20x

X = 100 mL

HELP
In \triangle JKL,△JKL, \angle J \cong \angle L,∠J≅∠L, LJ = 17LJ=17 and KL = 10KL=10. Find the length of JK.JK.

Answers

It's a isosceles right angled triangle

LJ=17KL=10

[tex]\\ \sf{:}\Rrightarrow JK^2=17^2+10^2[/tex]

[tex]\\ \sf{:}\Rrightarrow JK^2=289+100[/tex]

[tex]\\ \sf{:}\Rrightarrow JK^2=389[/tex]

[tex]\\ \sf{:}\Rrightarrow JK=19.72[/tex]

Pls help ASAP
Give the domain and range

Answers

Answer:

D: {-2, 0, 2}

R: {-1, 1, 3

Please answer these!!!! :D

Answers

Question 7: greater than

The combined area of the photo and mat needs to be 224 square inches. The equation that represents the combined area is
(2w +8)(2w + 10) = 224, where w represents the width of the mat around the photo.
What should the width of the mat be?
Enter your answer as the correct value, including units, like this: 42 meters
Be sure to use the correct units from the context of the problem

Answers

The width of the mat around the photo is 3 inches

The combined area of the of the photo and math = 224 square inches

The combined area is represented as:

(2w +8)(2w + 10) = 224

Expand the equation using the distributive rule

[tex]4w^2+20w+16w+80=224\\\\4w^2+36w+80-224=0\\\\4w^2+36w-144=0[/tex]

Divide through by 4

[tex]w^2+9w-36=0[/tex]

Factorize the resulting quadratic equation to solve for w

[tex]w^2-3w+12w-36=0\\\\w(w-3)+12(w-3)=0\\\\(w-3)(w+12)=0[/tex]

w  -  3  =  0

w   =  3

w  +  12  =  0

w   =  -12

The width of the mat around the photo is 3 inches

Learn more on area here: https://brainly.com/question/20968176

The width of the mat around the photo is 3 inches

Combined area:

2w +8)(2w + 10) = 224

where,

w = width of the mat around the photo

(2w +8)(2w + 10) = 224

open parenthesis

4w² + 20w + 16w + 80 = 224

4w² + 36w + 80 - 224 = 0

4w² + 36w - 144 = 0

divide through by 4

w² + 9w - 36 = 0

solve quadratic equation using factorization method

w² + 12w - 3w - 36 = 0

w(w + 12) - 3(w + 12) = 0

(w + 12) (w - 3) = 0

w + 12 = 0 or w - 3 = 0

w = -12 or w = 3

The width of the mat around the photo cannot be a negative value.

Therefore, the width of the mat around the photo is 3 inches

Learn more about quadratic equation:

https://brainly.com/question/1214333

84/120 equivalent fraction

Answers

Answer:

7/10

this should work

Step-by-step explanation:

which value is NOT equivalent to the others 3^4 3+3+3+3 3^2x 3^2 3x3x3x3

Answers

Answer:

3+3+3+3

Step-by-step explanation:

Hopefully I didn't get confused

3^4 vs 3+3+3+3 vs (3^2)(3^2) vs 3x3x3x3

Well the best way to do it is to do each

3^4=81

3+3+3+3=12

3^(2+2)=81

3x3x3x3=81

Therefore 3+3+3+3 is not equilvilent


Kesha went for a drive in her new car. She drove at a speed of 51.2 miles per hour for 2 hours. For how many miles did she drive?

Answers

Answer:

102.4

Step-by-step explanation:

51.2 x 2 = 102.4

Can somebody pls solve this equation my brain hurts.

Answers

The answer is C and D

Because when a negative value is be multiplied by a positive value the solution will be negative

Hope this helps!
Brainliest is much appreciated!

Meadow Academy's spring festival is coming up, and Ms. Rivera is in charge of ordering the butterfly kits again. She knows she ordered 6 cases of butterfly kits last year but can't remember how many kits come in a case. When she checks the records, Ms. Rivera finds that the school used 417 of the butterfly kits last year and had 63 left over after the festival. How many butterfly kits come in each case? ​

Answers

Answer:

Step-by-step explanation:

its 80 i just did the question

Each case contains 80 butterfly kits.

What is unitary method ?

Unitary method is a mathematical technique for finding the value of a single unit and then deriving the given unit by multiplying with it.

According to the given question Ms. Rivera ordered 6 cases of butterfly kits last year out of which the school used 417 of the butterfly kits and had 63 left over after the festival.

So, the total no. of butterfly kits is (417+63) = 480 kits and it was contained in 6 boxes.

∴ The no. of butterfly kits in each case is 480/6 which is

= 80 butterfly kits.

learn more about unitary method here :

https://brainly.com/question/23423168

#SPJ2

Kelly base 3328 cookies each year she bakes twice as many cookies in October then in the other much how many cookies does Kelly back in December

Answers

256 Cookies
There are 12 months and twice the amount of cookies in one month is equal to an extra month. So do 3328/13=256.

Find the center and radius of the circle with the equation: (x=5)2 +(4-2)3-25

Answers

Answer:

center = (5 ,-3) and radius = 5

Step-by-step explanation:

Determine the slope from the given graph below:

The slope is 4
The slope is -4
The slope is−14
The slope is -2

Answers

The slope of the line is -4

Answer:

-4

Step-by-step explanation:

rise over run

rise being y axis

run being x axis

in this case y intercept is 4 and x intercept is1

Examine the figure. What is the measure of angle b?

Answers

B = 180-31

B = 149

Answer: 149

Solve for x; x: 6 = 54: 162 A. 1 B. 2 C. 3 D. 4
find x​

Answers

Answer:

x = 2

Step-by-step explanation:

x:6 = 54:162

What is 54 to 162?

162/54 = 3.

So x times 3 should equal 6.

6/3 = 2.

x = 2

Let's confirm,

2:6 = 54:162

:)

Answer:

8 - 10

8 + 10

Step-by-step explanation:

edmentum/plato

Help help math math

Answers

Answer:

There are 24 different combinations.

Step-by-step explanation:

2x4x3= 24

expand the following 8(x-3)​

Answers

Answer:

8x-24

Step-by-step explanation:

First you do:

8×x which is 8x

Then you do:

8×-3 which is -24

Then you put it into 1 expression:

8x-24

Answer:

8−24

Thank You!

Pls help i neeed to get my grade up badly

Answers

Step-by-step explanation:

12 - 1/2r = ( 13 - 3/2r ) - ( 1 - r )

r - 13/6 = ( 7r - 3/2 ) - ( 2/3 + 6r )

13r + 20 = ( 6r + 7 ) + ( 13 + 7r )

-12 + r = ( -8 - r ) + ( 2r - 4 )

please explain how to do this. tried to solve but cant do it

Answers

Answer:

2.55km

Step-by-step explanation:

[tex]d=st[/tex]

where:

   d=distance

   s=speed

   t=time

[tex]s=\frac{3.4 \ \text{km}}{\text{hr}}\\[/tex]

[tex]t=0.75 \text{hr}[/tex]

[tex]d=st=(\frac{3.4 \text{km}}{\text{hr}})(0.75 \text{hr}})=2.55 \text{km}\\[/tex]

Answer:

[tex]3\frac{2}{5}[/tex] × [tex]\frac{3}{4}[/tex] [tex]= 2\frac{11}{20}[/tex] km

         = 2.55 km

Express your answer in scientific notation. PLS HELP

Answers

10^2=100
3600-6.3-100= 3493.7

hope this helps!

%
Only 30% of the donuts are left in the box after the party. I counted the
donuts and there are 18 donuts left. How many donuts were in the box to
start with?
donuts

Answers

Answer:

It's be 60 because 30% of 60 is 18. Hope that helped :)

If answer is correct I will mark as brainliest.
which of the following expresses the possible number of positive real solutions for the polynomial equation shown below?

5x^3+x^2-7x+28=0

A. Zero

B. Two or Zero

C. One

D. Three or one​

Answers

Answer:

No positive real solutions.So the answer is zero.

Step-by-step explanation:

7
Kali developed her own website to advertise her babysitting business. In June she had 5,234 people visit her site. In July she had a 12 percent decrease in visitors. Approximately how
many people visited Kali's website in July?
A 5862
B 5222
C 4605
4673

Answers

Answer:

4606

Step-by-step explanation:

5234 · 0.12 = 628

5234 - 628 = 4606

Answer:

The answer to this question should be C: 4605.

Step-by-step explanation:

For this problem we need to know what 12% of 5,234 is. 12% of 5,234 is 628.08. Since their was a decrease in visitors we need to subtract 5,234-625.08=4,605.92. The probelm states that we need to find the "Approximate number", so have the .92 doesnt matter. So therefore the answer to this probelm is C: 4605.

yw :)

In AJKL, j = 75 cm, k = 23 cm and

Answers

Answer:

The length of side j is 11.85cm

Step-by-step explanation:

Given that

In triangle JKL,

Side k=LJ=3.7cm

To find side j=KL:

By using sine rule,

We can write as

Using property of triangle,

Thus,

The length of side j is 11.85cm

Help pleasee :(
no links.

Answers

-2/12 is a
-0.1 is b
1/9 is c

Hope you find this helpful!
Brainliest and a like is much appreciated!

LAST ATTEMPT MARKING AS BRAINLIEST!! (Graph the image of the figure using the dilation given)

Answers

Answer:

There ya go

Step-by-step explanation:

the difference of 3 times a number and 18 is 39 what is the number

Answers

The answer is 13 because if you divide 39 by 3 you will get your answer.

Answer: 39

(3*(19))-18 = 39

57-18 = 39 we have the correct answer

5. Find cos theta if sin theta= -12/13
and tan theta > 0. (6 points)

Answers

[tex]\text{Given that,}\\\\\sin \theta = -\dfrac{12}{13}\\\\\implies \sin^2 \theta = \dfrac{144}{169}\\\\\implies 1- \cos^2 \theta = \dfrac{144}{169}\\\\\implies \cos^2 \theta = 1- \dfrac{144}{169}\\\\\implies \cos^2 \theta = \dfrac{25}{169}\\\\\implies \cos \theta = \pm \sqrt{\dfrac{25}{169}} = \pm \dfrac 5{13}\\\\\\\text{Since,}~ \tan \theta >0,\\\\\cos \theta =- \dfrac{5}{13}[/tex]

When solving a quadratic in the form ax2 + bx + c = 0 we are really finding the x–intercepts. These x–intercepts are also called roots. What is another term for roots or x-intercepts? put it in a full sentence for me please

Answers

Answer:

  solutions

Step-by-step explanation:

Another term for the roots or x-intercepts of the standard-form quadratic equation is "solutions." These are the values of x that make the equation true.

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