Answer:
The z-score for this data is Z = -0.26.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
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.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
This is based on knowledge that in the U.S., the mean PAL is 1.65 and the standard deviation is 0.55.
This means that [tex]\mu = 1.65, \sigma = 0.55[/tex]
A study took a random sample of 51 people who lived in low income neighborhoods and found their mean PAL to be 1.63.
This means that [tex]n = 51, X = 1.63[/tex]
Using a one-sample z test, what is the z-score for this data
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{1.63 - 1.65}{\frac{0.55}{\sqrt{51}}}[/tex]
[tex]Z = -0.26[/tex]
The z-score for this data is Z = -0.26.
can you help please I have no clue
Answer:
6, 15, 24, 33
Step-by-step explanation:
Basically, the number on top of the sigma represents the number of terms total in that sequence, and on the right you have the equation in which you can plug in whichever value that falls into what the top number says to find the output. In other words, just plug in 1 for k to find a1, 2 for k to find a2, etc.
Hope that helps!
A wheelchair ramp with a length of 61 inches has a horizontal distance of 60 inches. What is the ramp’s vertical distance
Answer:
Step-by-step explanation:
The solution triangle attached below :
Since we have a right angled triangle, we can make use of Pythagoras rule to obtain the vertical distance, x
Recall :
Hypotenus² = opposite² + adjacent²
Hence,
x² = 61² - 60²
x² = 3721 - 3600
x² = 121
x = √121
x = 11
Vertical distance equals 11 inches
Enter an equation in point-slope form for the line.
Slope is −6 and (1, 1) is on the line.
Answer:
y - 1 = -6(x - 1)
General Formulas and Concepts:
Algebra I
Point-Slope Form: y - y₁ = m(x - x₁)
x₁ - x coordinate y₁ - y coordinate m - slopeStep-by-step explanation:
Step 1: Define
Identify
Point (1, 1)
Slope m = -6
Step 2: Find Equation
Substitute in variables [Point-Slope Form]: y - 1 = -6(x - 1)Which expression is equivalent to -9x-1y-9/-15x5y-3?
Answer: -9x-1y-9/
Step-by-step explanation:
Answer: b
Step-by-step explanation:
I really dont like edge
ABC ∆ where Angle A =90° , AB = 12 m, AC = 9 m . Find BC ?
( Show all your workings )
best answer will marked as brainalist
dont put fake ones
Answer:
15m
Step-by-step explanation:
Use Pythagoras
Folow the steps in the image
Answer:
:] brainlist me friends
List the angles in order from the smallest to the largest.
Answer:
D. <S, <R, <T
Step-by-step explanation:
Recall: On a triangle, the bigger an angle measure the longer the side opposite it and vice versa.
In ∆RST,
The longest side, SR = 22, is opposite to <T
Therefore, <T is the biggest angle.
Medium side, ST = 21, is opposite to <R, therefore,
<R is the medium angle measure
The smallest angle measure <S is opposite to the shortest side, RT.
Angels I'm order form the smallest to largest will be:
<S, <R, <T
What is the smallest 6-digit- palindrome (a number that reads the same forward and backward) divisible by 99
Answer:
108801
Step-by-step explanation:
Palindrome as defined in the given question as a number which reads the same forward and backward. Examples are: 1001, 20202, 1331 etc.
Thus, to determine the smallest 6-digit palindrome divisible by 99 without a remainder, the digits should be in the form of abccba.
Therefore, the smallest 6-digit palindrome that can be divided by 99 is 108801.
So that,
108801 ÷ 99 = 1099
The thickness X of aluminum sheets is distributed according to the probability density function f(x) = 450 (x2 - x) if 6 < x < 12 0 otherwise 5-1 Derive the cumulative distribution function F(x) for 6 < x < 12. The answer is a function of x and is NOT 1! Show the antiderivative in your solution. 5-2 What is E(X) = {the mean of all sheet thicknesses)? Show the antiderivative in your solution.
Solution :
Given :
[tex]f(x) = \left\{\begin{matrix}\frac{1}{450}(x^2-x) & \text{if } 6 < x < 12 \\ 0 & \text{otherwise}\end{matrix}\right.[/tex]
1. Cumulative distribution function
[tex]$P(X \leq x) = \int_{- \infty}^x f(x) \ dx$[/tex]
[tex]$=\int_{- \infty}^6 f(x) dx + \int_{6}^x f(x) dx $[/tex]
[tex]$=0+\int_6^x \frac{1}{450}(x^2-x) \ dx$[/tex]
[tex]$=\frac{1}{450} \int_6^x (x^2-x) \ dx$[/tex]
[tex]$=\frac{1}{450}\left[\frac{x^3}{3}-\frac{x^2}{2}\right]_6^x$[/tex]
[tex]$=\frac{1}{450}\left[ \left( \frac{x^3}{3} - \frac{x^2}{2}\left) - \left( \frac{6^3}{3} - \frac{6^2}{2} \right) \right] $[/tex]
[tex]$=\frac{1}{450}\left[\frac{x^3}{3} - \frac{x^2}{2} - 54 \right]$[/tex]
2. Mean [tex]$E(x) = \int_{- \infty}^{\infty} \ x \ f(x) \ dx$[/tex]
[tex]$=\int_{6}^{12}x . \left( \frac{1}{450} \ (x^2-x)\right)\ dx$[/tex]
[tex]$=\frac{1}{450} \int_6^{12} \ (x^3 - x^2) \ dx$[/tex]
[tex]$=\frac{1}{450} \left[\frac{x^4}{4} - \frac{x^3}{3} \right]_6^{12} \ dx$[/tex]
[tex]$=\frac{1}{450} \left[ \left(\frac{(12)^4}{4} - \frac{(12)^3}{3} \right) - \left(\frac{(6)^4}{4} - \frac{(6)^3}{3} \right) $[/tex]
[tex]$=\frac{1}{450} [4608 - 252]$[/tex]
= 17.2857
Your sample is normally distributed with a mean age of 36. The standard deviation in this sample is 4 years. You would expect:
Kindly find complete question attached below
Answer:
Kindly check explanation
Step-by-step explanation:
Given a normal distribution with ;
Mean = 36
Standard deviation = 4
According to the empirical rule :
68% of the distribution is within 1 standard deviation of the mean ;
That is ; mean ± 1(standard deviation)
68% of subjects :
36 ± 1(4) :
36 - 4 or 36 + 4
Between 32 and 40
2.)
95% of the distribution is within 2 standard deviations of the mean ;
That is ; mean ± 2(standard deviation)
95% of subjects :
36 ± 2(4) :
36 - 8 or 36 + 8
Between 28 and 44
3.)
99% is about 3 standard deviations of the mean :
That is ; mean ± 3(standard deviation)
99% of subjects :
36 ± 3(4) :
36 - 12 or 36 + 12
Between 24 and 48
What is the solution to the following inequality X/-2 > 5
Answer:
x < -10
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightEquality Properties
Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of EqualityStep-by-step explanation:
Step 1: Define
Identify
x/-2 > 5
Step 2: Solve for x
[Multiplication Property of Equality] Multiply -2 on both sides: x < -10[tex]\large {\mathsf {\red{\underbrace {\overbrace{\blue{ {\pink}{Answєr}}}}}}} \: [/tex]
x > - 10
[tex] \large \mathtt \green{Step-by-step \: explanation : }[/tex]
[tex] \small \sf \frac{x}{ - 2} > 5 \\ [/tex]
Solve for x
[tex] \small \sf \frac{x}{ - 2} > 5 \\ [/tex]
common denominator is 2
[tex]\small \sf ➪ \frac{2x}{ - 2} >2 \times 5 \\ [/tex]
[tex]\small \sf ➪ \frac{ \cancel{2}x}{ - \cancel{ 2}} >2 \times 5 \\ [/tex]
➪ - x > 2 × 5
➪ - x > 10
multiply by - 1
➪ - x × - 1 > 10 × - 1
x > - 10
Please Help NO LINKS
[tex]V = 864\pi[/tex]
Step-by-step explanation:
Since one of the boundaries is y = 0, we need to find the roots of the function [tex]f(x)=-2x^2+6x+36[/tex]. Using the quadratic equation, we get
[tex]x = \dfrac{-6 \pm \sqrt{36 - (4)(-2)(36)}}{-4}= -3,\:6[/tex]
But since the region is also bounded by [tex]x = 0[/tex], that means that our limits of integration are from [tex]x=0[/tex] (instead of -3) to [tex]x=6[/tex].
Now let's find the volume using the cylindrical shells method. The volume of rotation of the region is given by
[tex]\displaystyle V = \int f(x)2\pi xdx[/tex]
[tex]\:\:\:\:\:\:\:= \displaystyle \int_0^6 (-2x^2+6x+36)(2 \pi x)dx[/tex]
[tex]\:\:\:\:\:\:\:= \displaystyle 2\pi \int_0^6 (-2x^3+6x^2+36x)dx[/tex]
[tex]\:\:\:\:\:\:\:= \displaystyle 2\pi \left(-\frac{1}{2}x^4+2x^3+18x^2 \right)_0^6[/tex]
[tex]\:\:\:\:\:\:\:= 864\pi [/tex]
A population has mean j = 18 and standard deviation o = 20. Find I, and oz for samples of size n = 100, Round your answers to
one decimal place if needed,
Answer:
))
Step-by-step explanation:
just place your decimal once to the left I think
A researcher believes that 9% of males smoke cigarettes. If the researcher is correct, what is the probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%
Answer:
0.0070 = 0.70% probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
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.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
A researcher believes that 9% of males smoke cigarettes.
This means that [tex]p = 0.09[/tex]
Sample of 664
This means that [tex]n = 664[/tex]
Mean and standard deviation:
[tex]\mu = p = 0.09[/tex]
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.09*0.91}{664}} = 0.011[/tex]
What is the probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%?
Proportion below 9 - 3 = 6% or above 9 + 3 = 12%. Since the normal distribution is symmetric, these probabilities are equal, so we find one of them and multiply by 2.
Probability the proportion is below 6%
P-value of Z when X = 0.06. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.06 - 0.09}{0.011}[/tex]
[tex]Z = -2.7[/tex]
[tex]Z = -2.7[/tex] has a p-value of 0.0035
2*0.0035 = 0.0070
0.0070 = 0.70% probability that the proportion of smokers in a sample of 664 males would differ from the population proportion by greater than 3%
what is the value of x?
what is the value of y?
type in an integer or decimal
9514 1404 393
Answer:
x = 5.6y = 65Step-by-step explanation:
There are a couple of relations that are applicable to these questions.
the product of segment lengths of crossed chords is the same for both chordsthe angle formed at crossed chords is the average of the intercepted arc measures__
The segment lengths relation tells us ...
10x = 8×7 . . . . . . products of segment lengths are equal
x = 56/10 = 5.6 . . . . divide by 10
__
The value of y° is the average of the intercepted arcs:
y° = (85° +45°)/2 = 65°
_____
Additional comment
This diagram does not have enough information to allow computation of z. We would need to know the intercepted arc, or the length of the secant that meets tangent z.
one number is seven less than the second number. five times the first is 9 more than 6 times the second. find the numbers
Step-by-step explanation:
2nd number = x
1st number = x - 7
5 (x - 7) = 6x + 9
5x - 35 = 6x + 9
- x = 44
x = - 44
1st number = -51
2nd number = -44
Proof: 5 (-51) = 6(-44) + 9
-255 = -264 + 9
-255 = -255
hope it helps.
Also, I think that Brainly is an awesome app, but there's an app which is doing great work for me in maths, named Gauthmath. I will suggest it. Video concepts and answers from real tutors.
what is the y-intercept of the line shown below?
A:3/4
B:2
C:3
D:4
The y-intercept is the y value where the blue line crosses the Y axis which is the vertical black line.
The line crosses at the number 4, so the y-intercept is 4
Answer: D. 4
At one point in history, the NBA finals required that one of the two teams win at least three of five games in order to win the Championship. If one team wins the first two games, what is the probability that the same team wins the Championship, assuming that the two teams are well matched and each team is equally likely to win each game
Answer:
50% i believe
Step-by-step explanation:
because in every scenario theres 2 teams and if they are well matched it be half and half on every game assuming they're the same level of comp
Type your answer
(1 out of 4)
What is the value of the function when x = 3 in the
piecewise function
g(x) =
3x when x > 1
- 2x when x < 1
Answer:
9
Step-by-step explanation:
Which solution finds the value of x in the triangle below?
A right triangle is shown. The hypotenuse has a length of 8. Another side has a length of x. The angle between the hypotenuse and the other side is 60 degrees.
Answer:
4
Step-by-step explanation:
Since this is a right triangle, and one of the angles measures 60 degrees, we can conclude that the last side measures 30 degrees.
We can see that this is a 30-60-90 degree triangle.
The rules of 30-60-90 degree triangles are that the side opposite the 90 degree angle, or the hypotenuse can be measured with the variable [tex]2a[/tex]. The side opposite the 30 degree angle can be measured with [tex]a[/tex], and the side opposite the 60 degree angle will be measured with [tex]a\sqrt{3}[/tex].
We can see that 8 represents [tex]2a[/tex] because it is the hypotenuse. Since the side marked [tex]x[/tex] is separated by the hypotenuse by an angle of 60 degrees, we note that side marked [tex]x[/tex] is opposite the angle measuring 30 degrees. We note that the side opposite 30 degrees is marked [tex]a[/tex], and since we already know that 8 is equal to [tex]2a[/tex], we realize that the side marked x is equal to [tex]a[/tex], or 4.
The value of x in the triangle is 4.
What is the Pythagorean theorem ?
The square of the length of the hypotenuse of a right triangle equals the sum of the squares of the lengths of the other two sides.
It is given this is a right triangle, and one of the angles measures 60 degrees, we can conclude that the last side measures 30 degrees. By the sum of all the three interior angles of a triangle is 180 degrees
The side opposite the 90 degree angle, or the hypotenuse can be measured with the variable '2a' . The side opposite the 30 degree angle can be measured with 'a' , and the side opposite the 60 degree angle will be measured with 'a√3'.
8 represents '2a' because it is the hypotenuse. Since the side marked x is separated by the hypotenuse by an angle of 60 degrees, we note that side marked x is opposite the angle measuring 30 degrees. We note that the side opposite 30 degrees is marked 'a', and since we already know that 8 is equal to '2a', we realize that the side marked x is equal to
'a' , or 4.
2a=8
a=4
x=a=4
so, the the value of x in the triangle is 4.
Learn more about the Pythagorean theorem here:
https://brainly.com/question/24154260
#SPJ5
Help please!!
The triangles are similar by:
the SAS similarity theorem.
the ASA similarity theorem.
the AA similarity postulate.
None of the choices are correct.
the SSS similarity theorem.
What is the gradient of the graph shown? Give your answer in simplest form
Answer:
gradient = 2
line: y = 2x - 4
Step-by-step explanation:
Find the slope from the slope intercept formula
y = mx + b
b is the y intercept
b = -4 and the point is (0,-4)
So far the equation looks like this.
y = mx - 4
Use the other intercept (x intercept) to find m
x = 2
y = 0
0 = m*2 - 4 Add 4 to both sides
4 = 2m Divide by 2
4/2 = m
m = 2
So the gradient or slope is 2
If A = {x, y, z} then the number of non-empty subsets of A is ________.
a) 8 b) 5 c) 6 d) 7
Answer:
(d) 7
Step-by-step explanation:
The total number of subsets that can be derived from a set with n elements is given by;
2ⁿ
Out of these subsets, there is one empty set. Therefore, the total number of non-empty subsets is given by;
2ⁿ - 1
Given:
A = {x, y, z}
Set A has 3 elements. This means that n = 3
Therefore, the total number of subsets that can be derived from set A is
2ⁿ = 2³ = 8
One of these 8 subsets is an empty set, therefore, the total number of non-empty subsets of A is;
2ⁿ - 1 = 2³ - 1
8 - 1 = 7
This can be checked by writing all the possible subsets of A as follows;
∅
{x}
{y}
{z}
{x, y}
{y, z}
{x, z}
{x, y, z}
Removing the empty set ∅, the non-empty subsets of A are;
{x}
{y}
{z}
{x, y}
{y, z}
{x, z}
{x, y, z}
The circumference of a circle is 14 inches. Find the circle's radius and diameter.
Please help :)
Can anyone help me please? I've been trying for so long, but I can't figure out the answer to this problem. Picture attached. Thank you so much.
Answer:
C
Step-by-step explanation:
Start by simplifying what you can in each radicalfor example, the
∛(xy⁵)= y∛(xy²)
and
∛(x⁷y¹⁷)=x²y⁵∛(xy²)
So know our equation looks like
y∛(xy²)*x²y⁵∛(xy²)
Now because what's inside the radical is the same we can combine them
y⁶x²∛(xy²)²
distribute the square
so
∛(xy²)²= ∛(x²y⁴)= y∛(x²y)
and finally,
y⁶x²*y∛(x²y)= y⁷x²∛(x²y)
this is equal to option C
The following multiple regression printout can be used to predict a person's height (in inches) given his or her shoe size and gender, where gender = 1 for males and 0 for females.
Regression Analysis: Height Versus Shoe Size, Gender
Coefficients
Term Coef SE Coef T-value P-value
Constant 55.24 1.05 52.61 0.000
Shoe Size 1.164 0.13 0.000
Gender 2.574 0.489 5.26 0.000
Required:
a. Find the value of the test statistic for shoe size.
b. Is the regression coefficient of shoe size statistically significant?
c. Does the variable shoe size belong in the model?
d. Interpret the regression coefficient of Gender.
Answer:
a. 8.95
b. it is
c. yes it belongs
d. males are 2.574 taller than females on average.
Step-by-step explanation:
GIven the regression outpuit that we have in this question, the value of the t test statistics for the shoe size can be solved as
a. test statistic = 1.164/0.13
t test = 8.95
b. the regression coefficient of shoe size is 1.164, this is statistically significant
c. Yes the variable shoe size does belong to the model.
d. The regression coefficient of gender shows that on the average, while holding other variables constant, males are 2.574 inches taller than the their female counterparts.
જ્યારે જહાંગીરની ઉંમર 18 વર્ષ થશે ત્યારે અકબરની ઉંમર 50 વર્ષ થર્શ.
જ્યારે અકબરની ઉંમર જહાંગીરની ઉંમર કરતા 5 ઘણી હશે ત્યારે
અકબરની ઉમર કેટલી હશે?
A) 36
B) 40
C) 44
D) 48
Answer:
C: 44
Step-by-step explanation:
36x^2=y^2
Does the equation define y as a function of x ?
Answer:
ya the equation divides y as a function of x
Can someone give me the letter to all answers 1-4 or at least one 3
Answer:
hello there here are your answers:
1) a- 12, 18, 24, 30, 36
2) b- 31
3) a-communitive property of addition
4) a- 6a
Step-by-step explanation:
1: go through all the numbers and add 6 like 12+6=16 etc.
2: the common difference is 4 so 27+4 =31
3: communitive property because you can change the number in any order and still get the same sum
4: 6a because only 24ab has a b in it
Which of the following numbers is rational? Assume that the decimal patterns continue.
Answer:
[tex]\sqrt{49}[/tex]
Step-by-step explanation:
Define a rational number by a number able to expressed a fraction where the denominator is not 0 or 1.
Non-terminating (never-ending) decimals cannot be expressed as a fraction and therefore are irrational. However, recall that [tex]\sqrt{49}=7[/tex], which can be expressed as a fraction (e.g. [tex]\frac{14}{2}[/tex], etc). Thus, the answer is [tex]\boxed{\sqrt{49}}[/tex].
A box contains 5 white balls, 3 black balls, and 2 red balls.A-What is the probability of drawing a white ball?B- How many white balls must be added to the box so that the probability of drawing a white ball is 3/4?C-How many black balls must be added to the original assortment so that the probability of drawing a white ball is 1/4?
Answer:
[tex](a)\ P(White) = \frac{1}{2}[/tex]
(b) 10 additional white balls
(c) 10 additional black balls
Step-by-step explanation:
Given
[tex]White = 5[/tex]
[tex]Black =3[/tex]
[tex]Red = 2[/tex]
Solving (a): P(White)
This is calculated as:
[tex]P(White) = \frac{White}{Total}[/tex]
[tex]P(White) = \frac{5}{5+3+2}[/tex]
[tex]P(White) = \frac{5}{10}[/tex]
[tex]P(White) = \frac{1}{2}[/tex]
Solving (b): Additional white balls, if [tex]P(White) = \frac{3}{4}[/tex]
Let the additional white balls be x
So:
[tex]P(White) = \frac{White+x}{Total+x}[/tex]
This gives:
[tex]\frac{3}{4} = \frac{5+x}{10+x}[/tex]
Cross multiply
[tex]30+3x = 20 + 4x[/tex]
Collect like terms
[tex]4x - 3x = 30 - 20[/tex]
[tex]x = 10[/tex]
Hence, 10 additional white balls must be added
Solving (c): Additional black balls, if [tex]P(White) = \frac{1}{4}[/tex]
Let the additional black balls be x
So:
[tex]P(White) = \frac{White}{Total+x}[/tex]
So, we have:
[tex]\frac{1}{4} = \frac{5}{10+x}[/tex]
Cross multiply
[tex]10+x = 5 * 4[/tex]
[tex]10+x = 20[/tex]
Collect like terms
[tex]x = 20 -10[/tex]
[tex]x = 10[/tex]
Hence, 10 additional black balls must be added