Answer:
x=6
Step-by-step explanation:
13(x-3)=39
Divide each side by 13
13/13(x-3)=39/13
x-3 = 3
Add 3 to each side
x-3+3 = 3+3
x = 6
Answer:
x=6
Step-by-step explanation:
expanding we get
13x-39=39
13x=39+39
13x=78
x=78/13
x=6
Which of the following functions has a vertical asymptote at x = 2, a horizontal
asymptote at f(x) = 1, and a root at x = -1?
A.f(x) = 2 + 1
B.f(x) = x 2 + 1
c.f(x) = x 2 - 1
D.f(x) == +1
Answer:
First, an asymptote means that the function "tends to go" to a value, bt actually never reaches it.
The functions here are:
A.f(x) = 2 + 1
B.f(x) = x^2 + 1
c.f(x) = x^2 - 1
D.f(x) == +1
The functions are really poorly written, but i will try to answer this.
first:
"a root at x = -1"
Means that f(-1) = 0,
The only function that is zero when x = -1, is the option c.
f(-1) = (-1)^2 - 1 = 1 - 1 = 0.
Now, if we want to have a vertical asymptote at x = 2, then we should have a function like:
[tex]f(x) = \frac{something}{x - 2}[/tex]
So we want to have a quotient, where the denominator is equal to zero when x = 2, this will lead to a vertical asymptote.
I can not see this in the options provided, so i guess that the functions are just not well written.
For a horizontal asymptote, we have something like:
[tex]f(x) = \frac{something}{x} + 1[/tex]
So as x starts to grow, the first term in the function will start to decrease, until it becomes really close to zero (but is never equal to zero) so in that case we have an horizontal asymptote to f(x) = 1.
5 - (4 - 3x) = 10
how would u distubute in this problem
Answer:
x = 3
Step-by-step explanation:
Given
5 - (4 - 3x) = 10 ← distribute the terms in the parenthesis by - 1
5 - 4 + 3x = 10, that is
1 + 3x = 10 ( subtract 1 from both sides )
3x = 9 ( divide both sides by 3 )
x = 3
Identify whether each phrase is an expression, equation, or inequality.
Term
Phrase
Expression
3 - 53 =y
Inequality
7-5 <2.9
2 + 0
Equation
24"
t
Answer:
The identities of the terms are;
3 - 53 = y is an equation
7.5 < 2.9 is an inequality
2 + 0 is an expression
t is a term
24" is a term
Step-by-step explanation:
An equation is an expression with the equal to sign
3 - 53 = y is an equation
An inequality is a mathematical expression that contains an inequality sign
7.5 < 2.9 is an inequality
A term is a sole number or variable or the product of variables and numbers that come before and after mathematical operators such as +, ×, -, or ÷
t and 24" are terms.
The average weight of the top 5 fish caught at a fishing tournament was 12.3 pounds. Some of the weights of the fish are shown in the table.
What was the weight of the heaviest fish?
Answer:
14.6
Step-by-step explanation:
It is given that,
The average weight of the top 5 fish caught at a fishing tournament was 12.3 pounds. From the attached figure, the weight of 5 fish are given. We need to find the weight of Wayne S. fish.
Average = sum of terms/no of terms
Let the weight of Wayne S. is x. So,
Here the sum of terms is x+12.8+12.6+11.8+9.7 and the number of terms is 5.
[tex]12.3=\dfrac{x+12.8+12.6+11.8+9.7}{5}\\\\61.5=x+12.8+12.6+11.8+9.7\\\\61.5=x+46.9\\\\x=14.6[/tex]
So, the weight of the heaviest fish is 14.6.
Flight time from Houston to Orlando is 2 hours to 20 minutes. I arrived at Orlando at 4:15 pm. What time did I set of ?
Answer:
1:55 pm
Step-by-step explanation:
So, you arrive at 4: 15 pm in Orlando after a 2 hr and 20 minute flight from Houston. So, lets start with the easy part: let's subtract the 2 hrs part.
2 hrs earlier from 4:15 pm is 2:15 pm.
Then, you have to subtract the 20 minutes. Well, it's quite obvious that if you left at 2:00 pm, that would be a total of 2 hrs and 15 minutes. Just subtract the 15 minutes from the 2:15 pm. However, it's 20 minutes, not 15, so you have to still subtract that last five minutes.
So, 2:00 pm minus 5 minutes would equal 1:55 pm.
Which property justifies the following equation? 7[6+5+(-6)] = [6+(-6)+5] A.distributive B.commutative C.associative D.identity
Find the perimeter of rectangle whose length is 40 and the diagonal is 41 cm
Answer:
P = 98 cmStep-by-step explanation:
Given one side and diagonal of rectangle we can use Pythagorean theorem to calculate the other side of it.
[tex]L=40\, cm\\D=41\,cm\\W=\ ?\\\\W^2+L^2=D^2\\\\W^2+40^2=41^2\\\\W^2+1600=1681\\\\W^2=81\\\\W=9[/tex]
Perimeter:
P = 2W + 2L = 2•40 + 2•9 = 80 + 18 = 98
help please! Darren is finding the equation in the form y = m x + b for a trend line that passes through the points (2, 18) and (–3, 8). Which value should he use as b in his equation? a) –34 b) –19 c) 2 d) 14
Answer: d) 14
Step-by-step explanation:
Equation of a line passing through (a,b) and (c,d):
[tex](y-b)=\dfrac{d-b}{c-a}(x-a)[/tex]
Equation of a line passing through (2, 18) and (–3, 8):
[tex](y-18)=\dfrac{8-18}{-3-2}(x-2)\\\\\Rightarrow\ (y-18)=\dfrac{-10}{-5}(x-2)\\\\\Rightarrow\ (y-18)=2(x-2)\\\\\Rightarrow\ y-18=2x-4\\\\\Rightarrow\ y=2x-4+18\\\\\Rightarrow\ y=2x+14[/tex]
Comparing resulting equation [tex]y=2x+14[/tex] to [tex]y = m x + b[/tex], we get value of b= 14.
Hence, correct option is d) 14
A study was conducted on students from a particular high school over the last 8 years. The following information was found regarding standardized tests used for college admitance. Scores on the SAT test are normally distributed with a mean of 982 and a standard deviation of 198. Scores on the ACT test are normally distributed with a mean of 19.6 and a standard deviation of 4.5. It is assumed that the two tests measure the same aptitude, but use different scales.If a student gets an SAT score that is the 20-percentile, find the actual SAT score.SAT score =What would be the equivalent ACT score for this student?ACT score =If a student gets an SAT score of 1437, find the equivalent ACT score.ACT score =
Answer:
Actual SAT Score = 815.284
Equivalent ACT Score = 15.811
The equivalent ACT Score = 29.95
Step-by-step explanation:
From the given information:
Scores on the SAT test are normally distributed with :
Mean = 982
Standard deviation = 198
If a student gets an SAT score that is the 20-percentile
Then ;
P(Z ≤ z ) = 0.20
From the standard z-score for percentile distribution.
z = -0.842
Therefore, the actual SAT Score can be computed as follows:
Actual SAT score = Mean + (z score × Standard deviation)
Actual SAT score = 982 + (- 0.842 × 198)
Actual SAT score = 982 + ( - 166.716)
Actual SAT score = 982 - 166.716
Actual SAT Score = 815.284
Scores on the ACT test are normally distributed with a mean of 19.6 and a standard deviation of 4.5.
Mean = 19.6
Standard deviation = 4.5
Equivalent ACT Score = 19.6 + (- 0.842 × 4.5)
Equivalent ACT Score = 19.6 + ( - 3.789)
Equivalent ACT Score = 15.811
If a student gets an SAT score of 1437, find the equivalent ACT score.
So , if the SAT Score = 1437
Then , using the z formula , we can determine the equivalent ACT Score
[tex]z = \dfrac{X - \mu}{\sigma}[/tex]
[tex]z = \dfrac{1437 - 982}{198}[/tex]
[tex]z = \dfrac{455}{198}[/tex]
z =2.30
The equivalent ACT Score = 19.6 + (2.30 × 4.5)
The equivalent ACT Score = 19.6 + 10.35
The equivalent ACT Score = 29.95
Which term describes a time period marked by a change that begins a new period of development? century decade era millennium
Answer:
Era
Step-by-step explanation:
Century, Decade and Millennium have something in common and that which they have in common is that they are all measurement of time.
The keyword measurement implies that they are units of time just like seconds, minutes, hours, etc.
Century -> 100 years
Decade -> 10 years
Millennium -> 1000 years
However, era is used to describe events in history;
Take for instance; the era of the first generation of computer;
So, from the list of given options; Era best answers the question
An era describes a time period marked by a change that begins a new period.
An era :
begins with a significant eventgoes on for a period of time before it is replaced by another era. has distinct events from those of another eraExamples of eras include:
the Roaring Twenties the Progressive era The Cold War era The Age of EnlightenmentAll the eras mentioned above were distinct in how people behaved so in conclusion we can say that an era is a time period that begins a new period of development.
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The data represents the number of runs allowed by 8 college softball pitchers. {18, 49, 38, 41, 33, 44, 42, 22}
This Question is incomplete
Complete Question:
The data represents the number of runs allowed by 8 college softball pitchers. {18, 49, 38, 41, 33, 44, 42, 22}
What is the five number summary:
a) Minimum
b) Q₁
c) Median
d) Q₃
e) Maximum
Answer:
a) Minimum = 18
b) Q₁ = 27.5
c) Median = 39.5
d) Q₃ = 43
e) Maximum = 49
Step-by-step explanation:
From the above diagram, we were given the following set of data.
{18, 49, 38, 41, 33, 44, 42, 22}
Before answering any of the questions, we have to rearrange the data from the lowest to the highest (ascending order). Hence, we have:
{18, 22, 33, 38, 41, 42, 44, 49}
a) Minimum
{18, 22, 33, 38, 41, 42, 44, 49}
Looking at this set of arranged data, the minimum number is the least or lowest number.
This number is 18
b) Q₁
{18, 22, 33, 38, 41, 42, 44, 49}
Q₁ means First Quartile. The formula is = ¼(n + 1)th value
n = Number of terms in the data set = 8
= ¼(8 + 1)th value
= ¼(9)th value
= 2 1/4 value
= 2.25 value
In the above Question, the 2.25 value is the value between the second and third number.
Hence:
22+33/2 = 55/2 = 27.5
Therefore, Q₁ = 27.5
c) Median
{18, 22, 33, 38, 41, 42, 44, 49}
The median of the number is the number in the middle
For this data, we have 8 number, Hence the median is the sum of the 4th and 5th term divided by 2
4th term = 38
5th term = 41
= 38 + 41/ 2 = 79/2
= 39.5
Hence, the median = 39.5
d) Q₃
{18, 22, 33, 38, 41, 42, 44, 49}
Q₃ means Third Quartile. The formula is = ¾(n + 1)th value
n = Number of terms in the data set = 8
= ¾(8 + 1)th value
= ¾(9)th value
= 6 3/4 value
= 6.75 value
In the above Question, the 6.75 value is the value between the sixth and seventh number.
Hence:
42+44/2 = 86/2 = 43
Therefore, Q₃ = 43
e) Maximum
{18, 22, 33, 38, 41, 42, 44, 49}
Looking at this set of arranged data, the Maximum number is the highest number.
This number is 49
1) Complete the table
2) find the mean of the random variable x. Use the formula in the photo
Answer:
a. Please check the explanation for filling of the empty column on the table
b. The mean of the random variable x is 7/11
Step-by-step explanation:
a. Firstly, we are concerned with completing the table.
To do this, we simply need to multiply the values in the column of x by the values in the column of p(x)
Thus, we have the following;
2. 3 * 2/36 = 6/36
3. 4 * 3/36 = 12/36
4. 5 * 4/36 = 20/36
5. 6 * 5/36 = 30/36
6. 7 * 6/36 = 42/36
7. 8 * 5/36 = 40/36
8. 9 * 4/36 = 36/36
9. 10 * 3/36 = 30/36
10. 11 * 2/36 = 22/36
11. 12 * 1/36 = 12/36
b. We want to find the mean of the random variable x.
All what we need to do here is add all the values of x•P(x) together, then divide by 11.
Thus, we have
(2/36 + 6/36 + 12/36 + 20/36 + 30/36 + 42/36 + 40/36 + 36/36 + 30/36 + 22/36 + 12/36)/11
Since the denominator is same for all, we simply add all the numerators together;
(252/36) * 11 = 252/396 = 63/99 = 7/11
a number has 2,5 and 7 as its prime factors. what are the four smallest values it and take
Answer:
70, 140, 280, 350
Step-by-step explanation:
Obviously, it must have the factors 2, 5, 7 as a minimum, so the smallest value is 2×5×7 = 70.
Any of these primes can be added to the product. In increasing order, the smallest additional factors will be 2, 4, 5, 7, 8, 10, ...
So, the four smallest numbers with prime factors of 2, 5, and 7 are ...
70 = 2·5·7
140 = 2²·5·7
280 = 2³·5·7
350 = 2·5²·7
What is 25x + 67y if x = 23 and y = 36. Give explanation please!
Answer:
2987.
Step-by-step explanation:
25(23) + 67(36) = 575 + 2412 = 2987.
Hi there! Hopefully this helps!
------------------------------------------------------------------------------------------------------------
Answer: 2987
First we need to rewrite the equation. Since x = 23 and y = 36 the equation should look like this for easier steps:
25(23) + 67(36) = ?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Now since there numbers by other numbers in parentheses, we need to multiply them.
25 x 23 = 575.
67 x 36 = 2412.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Now that the equation is in its final form, we write it like this for the answer:
575 + 2412 =
2987.28.Neethi had 8
1
4
cups of flour and 3 liters of juice with her. She decided to make cupcakes and
distribute juice for her birthday.
a) A cupcake requires 3
4
cup of flour. How many cupcakes can she make?
Answer:
2 1/3 cupcakes
Step-by-step explanation:
A cupcake can make 3 four cups of flour
In 8 fourteen cups of flour, require (14 X 4)/(3 X 8) of cupcakes
= 56/24 = 2 1/3 cupcakes
1.2 Exit Ticket
POSSIBLE POINTS: 0.5
Below are the total number of students for each teacher in the Arts department. Round to the nearest tens place in order to estimate the total amount of
students enrolled in an art course,
132, 145, 97, 112, 128, 82
1
2
RE
Answer:
174
Step-by-step explanation:
Given
132, 145, 97, 112, 128, 82
Required
Estimate amount of students in an art class
This is calculated by obtaining the mean of the given data
[tex]Mean = \frac{\sum x}{n}[/tex]
Where n is the number of observations
So; n = 6
[tex]Mean = \frac{132+ 145+ 97+ 112+ 128+ 82}{6}[/tex]
[tex]Mean = \frac{696}{6}[/tex]
[tex]Mean = 174.0[/tex]
Hence, the estimated number of students is 174
Jolene bought 3 plants at a greenhouse. Each plant cost $2.50. To calculate the total cost of the plants, Jolene added (3(2)) + (3(0.50)). What property of multiplication did she use?*
A.Distributive Property
B.Associative Property
C.Commutative Property
D.Identity Property
Answer:
The answer is A.Distributive PropertyStep-by-step explanation:
Distributive property of multiplication has to do with the multiplication of numbers by the sum of that number
say in our given example $2.05.
When we decide to multiply 3 property with $2 and $0.5 which when added together will still give $2.05, we are using distributive property of multiplication.
Hence according to distributive property 3*$2.05 is the same as
3*$2 + 3*$0.5
5/8 divided by 11/9 divided by 1/4=
Answer:
45/22
Step-by-step explanation:
(a/b)/(c/d) = (a*d)/(b*c)
then
{(5/8)/(11/9)} / {1/4)}
= {(5*9)/(8*11)} / {1/4)
= {45/88} / {1/4}
= {45*4} / {88*1}
= 180/88
= 45 / 22
Jermiah answer 90% of the questions on his test correctly. There are 40 questions on the test
Answer:
36 answered correctly
Step-by-step explanation:
Hey there!
Well 90% of 40 is 36.
This is true because 90% as a fraction not simplified is 36/40 and when we do,
36 ÷ 40 we get .9.
And we move the decimal places 2 times to the right in .9 and we get 90%.
Hope this helps :)
Answer:
36
Step-by-step explanation:
Given that v = u + 10t, find y when
u= 6 and t = 9.
Answer:
hey here is the answer
Step-by-step explanation:
Subject of the formula:
It is a variable which is expressed in terms of other variables involved in the formula.
Formulas are written so that a single variable, the subject of the formula is on the L.H.S. of the equation. Everything else goes on the right side of the equation. We evaluate the formula by substituting for the literal numbers on the right hand side.
For example:
In the formula v = u + at, v is the subject.
To find v in the example, we substitute the values u, a and t in the R.H.S. of the equation.
Changing the subject of the formula:
To change the subject of a formula, begin with the variable to become the new subject, and apply inverse operation as for solving equations in the opposite order to the order conventions.
1. To make ‘u’ the subject of the formula in v = u + at,
[subtract at from both sides]
v - at = u
or, u = v - at
2. To make ‘t’ the subject of the formula, v = u + at,
[subtract u from both sides]
v - u = at
or, (v - u )/a = t
or, t = (v - u)/a
Change the Subject of a Formula
The value of the equation is v = 96 when u = 6 and t = 9
What is an Equation?Equations are mathematical statements with two algebraic expressions flanking the equals (=) sign on either side.
It demonstrates the equality of the relationship between the expressions printed on the left and right sides.
Coefficients, variables, operators, constants, terms, expressions, and the equal to sign are some of the components of an equation. The "=" sign and terms on both sides must always be present when writing an equation.
Given data ,
Let the equation be represented as A
Now , the value of A is
v = u + 10t be equation (1)
when u = 6 and t = 9
Substitute the value of u and t in the equation , we get
v = 6 + 10 ( 9 )
On simplifying the equation , we get
v = 6 + 90
v = 96
Therefore , the value of v is 96
Hence , the equation is v = 96
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Will give Brainliest, Please show work.
I need help
2x+10=14
x=2
Area: 14.4= 56
3x+16=25
3x=9
x=3
17x-1,7=37,4
17x=39,1
x=2,3
Scientists are studying the temperature on a distant planet. They find that the surface temperature at one location is 50° Celsius. They also find that the temperature decreases by 3° Celsius for each kilometer you go up from the surface. Let T represent the temperature (in Celsius), and let H be the height above the surface (in kilometers). Write an equation relating T to H, and then graph your equation using the axes below.
Answer:
T(H) = -3H + 50.
Step-by-step explanation:
The constant will be 50 degrees Celsius. The surface temperature at the location will not change. The temperature decreases by 3 degrees Celsius for every kilometer going up, so the slope will be -3 degrees.
You are trying to find the temperature on the planet, and you are changing the kilometers of altitude to find the temperature. The x-variable is your independent variable, which means that you will be changing the x-variable. So, H is your x-variable while T is your y-variable.
T = -3H + 50.
To graph, we can use the Math is Fun Function Grapher and Calculator. The graph is seen below.
Hope this helps!
The size of a television screen is given as 95 cm, correct to the nearest 5 cm.
Write down the upper bound of the size of the television screen.
Answer:
U B = 100.5
Step-by-step explanation:
the upper bound of the size of the television screen= 95.5 since it is corrected to the nearest 5 then the U B =100.5 cm
The upper bound of the size of the television screen is 100.5 cm
The conversion of the size of the television screen to the nearest 5cm from the initial size of 95 cm is = 100 cm.
Now, the upper bound of the size of the television screen which is 100 is can be determined by the addition of a half value to 100 cm:
i.e.
= (1/2) + 100 cm
= 0.5 + 100 cm
= 100.5 cm
Therefore, we can conclude that the upper bound of the size of the television screen is 100.5 cm
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When sketching a normal curve, what
value represents one standard deviation
to the right of the mean for the data set?
56, 54, 45, 52, and 48.
Answer:
The value representing one standard deviation to the right of the mean is 55.
Step-by-step explanation:
The provided data set is:
S = {56, 54, 45, 52, and 48}
Compute the mean and standard deviation as follows:
[tex]\mu=\frac{1}{n}\sum X=\frac{1}{5}\times [56+54+45+52+48]=51\\\\\sigma=\sqrt{\frac{1}{n}\sum (X-\mu)^{2}}=\sqrt{\frac{1}{5}\cdot {(56-51)^{2}+...+(48-51)^{2}}}=\sqrt{\frac{1}{5}\times 80}=4[/tex]
Compute the value representing one standard deviation to the right of the mean as follows:
[tex]X=\mu+1\cdot \sigma[/tex]
[tex]=51+(1\times 4)\\=51+4\\=55[/tex]
Thus, the value representing one standard deviation to the right of the mean is 55.
rational number 3 by 40 is equals to
Answer:
6/80, 9/120, 12/160 etc
Answer:
3/40 = 6/80 = 9/120 = 12/160 etc......
Hope it helps
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mr.wright judges the annual jelly bean challenge at the summer fair.every year he encourages the citizens in his town to guess the number of jelly beans in the jar.he keeps in record of everyones guesses and the number of the jelly beans each person was off by. what is the independent and dependent quantity?
Answer: Independent quantity : number of jelly beans in the jar guessed.
Dependent quantity : number of the jelly beans each person was off by.
Step-by-step explanation:
Independent quantity : A quantity that the experimenter can change or control.Dependent quantity : A quantity that depends on each independent quantity.In the given scenario, there are two quantities introduced:
number of jelly beans in the jar guessed. number of the jelly beans each person was off by.Since, "number of the jelly beans each person was off by." depends on "number of jelly beans in the jar guessed.".
So,
Independent quantity : number of jelly beans in the jar guessed.
Dependent quantity : number of the jelly beans each person was off by.
Given that T{X: 2<x ≤ 9} where x is an integer. what is n(T)
Answer:
n(T) = 7Step-by-step explanation:
Given the set T{X: 2<x ≤ 9} where x is an integer, the element of the set T will be {3, 4, 5, 6, 7, 8, 9}. note that from the inequality set 2<x ≤ 9, x is not equal to 2 but greater than 2. The inequality can be divided into two as shown;
If 2<x ≤ 9 then 2<x and x≤9
If 2<x, this means x>2 but not equal to 2. This is the reason why 2 is not contained in the set T.
Similarly if x≤9, this shows that x can not be greater than 9 but less than or equal to 9.
Since the set T = {3, 4, 5, 6, 7, 8, 9}, we are to find n(T). n(T) means cardinality of the set T and cardinality of a set is defined as the total number of element in a set.
Hence n()n(T) = 7 (since there are 7 elements in the set T)
what is the value of the angle ?
Answer:
47°
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles
124° is an exterior angle , thus
77 + ? = 124 ( subtract 77 from both sides )
? = 47°
Verify the identity. cot(x - pi/2) = -tan(x)
Answer:
See below.
Step-by-step explanation:
[tex]\cot(x-\frac{\pi}{2})=-\tan(x)[/tex]
Convert the cotangent to cosine over sine:
[tex]\frac{\cos(x-\frac{\pi}{2} )}{\sin(x-\frac{\pi}{2})} =-\tan(x)[/tex]
Use the cofunction identities. The cofunction identities are:
[tex]\sin(x)=\cos(\frac{\pi}{2}-x)\\\cos(x)=\sin(\frac{\pi}{2}-x)[/tex]
To convert this, factor out a negative one from the cosine and sine.
[tex]\frac{\cos(-(\frac{\pi}{2}-x ))}{\sin(-(\frac{\pi}{2}-x))} =-\tan(x)[/tex]
Recall that since cosine is an even function, we can remove the negative. Since sine is an odd function, we can move the negative outside:
[tex]\frac{\cos((\frac{\pi}{2}-x ))}{-\sin((\frac{\pi}{2}-x))} =-\tan(x)\\-\frac{\sin(x)}{\cos(x)} =-\tan(x)\\-\tan(x)\stackrel{\checkmark}{=}-\tan(x)[/tex]
How many gallons of 30% alcohol solution and how many of 60% alcohol solution must be mixed to produce 18 gallons of 50% solution?
Answer:
x = 6 gallons (of 30% alcohol)
y = 12 gallons (of 60% alcohol)
Step-by-step explanation:
Let
x = liters of 30% alcohol
y = liters of 60% alcohol
There are two unknowns, we need two equations
x + y = 18. (1)
0.30x + 0.60y = 0.50(x+y) (2)
From (1)
x + y = 18
y = 18-x
Substitute the value of y into (2) and solve for x:
0.30x + 0.60y = 0.50(x+y)
0.30x + 0.60(18-x) = 0.50(x+18-x)
0.30x + 10.8 - 0.60x = 0.50(18)
10.8 - 0.30x = 9
-0.30x = -1.8
Divide both sides by -0.30
x = 6 gallons (of 30% alcohol)
Substitute x=6 into (1) and solve for y:
x + y = 18
6 + y = 18
y = 12 gallons (of 60% alcohol)