Answer:
First Choice: As the number of hours spent on homework increases, the tests scores increase.
Step-by-step explanation:
The definition of a positive correlation is a relationship between two given variables, in which both variables are moving in the same direction. This can mean when one variable increases and the other variable increases, too, or one variable decreases and the other decreases as well.
The first choice is a positive correlation because both variables are changing (increasing) in the same direction. As you spend more time on homework, you're likely to get a higher test score.
The second choice cannot be a positive correlation because only one variable is having some kind of change (increasing). The doctor visits amount remains the same, so we can call this a zero-correlation relationship because the number of apples eaten yearly doesn't affect the amount of doctor visits. An apple a day keeps the doctor a way is just a proverb, not to be taken literally.
The third choice cannot be a positive correlation because the two variables are going different directions. Even though the number of times going to bed early is increasing, the number of times waking up late decreases, which is not moving in the same direction as the other variable.
The fourth choice cannot be a positive correlation because, similarly to the third choice, the two variables are going different directions. One variable is increasing, which is the amount of practice time. Meanwhile, the other variable is decreasing (going in the opposite direction), which is the number of games lost in a season.
How many centilitres are in 156000m^3
9514 1404 393
Answer:
1.56×10^10 cL
Step-by-step explanation:
There are 1000 liters in a cubic meter, so 10^5 centiliters in a cubic meter. The 1.56×10^5 cubic meters will then have ...
(1.56×10^5 m^3)×(10^5 cL/m^3) = 1.56×10^10 cL
_____
That's 15,600,000,000 cL.
"Centi-" is a prefix meaning 1/100.
How many women must be randomly selected to estimate the mean weight of women in one age group? We want 90% confidence that the sample mean is within 3.7 lbs of the populations mean, and population standard deviation is known to be 28 lbs.
Answer:
155 women must be randomly selected.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.9}{2} = 0.05[/tex]
Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].
That is z with a pvalue of [tex]1 - 0.05 = 0.95[/tex], so Z = 1.645.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
The population standard deviation is known to be 28 lbs.
This means that [tex]\sigma = 28[/tex]
We want 90% confidence that the sample mean is within 3.7 lbs of the populations mean. How many women must be sampled?
This is n for which M = 3.7. So
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]3.7 = 1.645\frac{28}{\sqrt{n}}[/tex]
[tex]3.7\sqrt{n} = 1.645*28[/tex]
[tex]\sqrt{n} = \frac{1.645*28}{3.7}[/tex]
[tex](\sqrt{n})^2 = (\frac{1.645*28}{3.7})^2[/tex]
[tex]n = 154.97[/tex]
Rounding up:
155 women must be randomly selected.
I NEED HELP PLEASE ASAP!!
Answer:
Option B, 1
Step-by-step explanation:
tan 45° = 1/1 = 1
PLEASE HELP ILL GIVE BRAINLIEST
Answer:
A. Combination.
B. 17020
Step-by-step explanation:
A. Determination whether it is permutation or combination.
From the question given above, we were told that the student body of 185 students wants to elect two (2) representatives.
This is clearly combination because it involves a selecting process (i.e selecting 2 out of 185).
NOTE: Combination involves selecting while permutation involves arranging.
B. Determination of the combination.
Total number of people (n) = 185
Number of chosen people (r) = 2
Number of combination (ₙCᵣ) =?
ₙCᵣ = n! / (n – r)! r !
₁₈₅C₂ = 185! / (185 – 2)! 2!
₁₈₅C₂ = 185! / 183! 2!
₁₈₅C₂ = 185 × 184 × 183! / 183! 2!
₁₈₅C₂ = 185 × 184 / 2!
₁₈₅C₂ = 185 × 184 / 2 × 1
₁₈₅C₂ = 34040 / 2
₁₈₅C₂ = 17020
A rectangular floor is 20 feet long and 16 feet broad. if it is to be paved with squared marbles of same size,find the greatest length of each squared marbles.
Answer:
4 ft
Step-by-step explanation:
I guess, the meaning is the largest marbles, so that we can pave the whole floor without cutting any marbles and leaving empty spots.
so, 20×16 ft²
we can have marbles 1/2 ft long. and it all fits well : 40×32 marbles.
we can have them 1 ft long, and it all fits well : 20×16 marbles.
we can have them 2ft long, and it still fits well : 10×8 marbles.
and so on.
so, actually, we are looking for the greatest common divisor (GCD) of 20 and 16. and that gives us the maximum length of a single marble to fulfill the requirement.
let's go for the prime factors starting with 2
20/2 = 10
10/2 = 5
5/3 fits not work
5/5 = 1 done
so, 20 = 2²×3⁰×5¹
16/2 = 8
8/2 = 4
4/2 = 2
2/2 = 1 done
16 = 2⁴
so, for the GCD I can only use powers of 2 (the only prime factors both numbers have in common).
and we have to use the smaller power of 2, which is 2, so, the GCD is 2² = 4
=>
the maximum length of the squared marbles is 4 ft.
that would pave the floor with 5×4 marbles completely.
A company that manufactures and bottles apple juice uses a machine that automatically fills 32-ounce bottles. There is some variation, however, in the amount of liquid dispensed into the bottles. The amount dispensed has been observed to be approximately normally distributed with mean 32 ounces and standard deviation 1 ounce. Determine the proportion of bottles that will have more than 30 ounces dispensed into them. (Round your answer to four decimal places.)
Answer:
The proportion of bottles that will have more than 30 ounces dispensed into them is 0.9772 = 97.72%.
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.
The amount dispensed has been observed to be approximately normally distributed with mean 32 ounces and standard deviation 1 ounce.
This means that [tex]\mu = 32, \sigma = 1[/tex]
Determine the proportion of bottles that will have more than 30 ounces dispensed into them.
This is 1 subtracted by the p-value of Z when X = 30, so:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{30 - 32}{1}[/tex]
[tex]Z = -2[/tex]
[tex]Z = -2[/tex] has a p-value of 0.0228.
1 - 0.0228 = 0.9772
The proportion of bottles that will have more than 30 ounces dispensed into them is 0.9772 = 97.72%.
A pool can be filled with water by a large pipe within six hours .A smaller pipe will take 9 hours to fill the pool.How long will it take to fill the pool if the two pipes operate together
Answer:
3.6 hours
Step-by-step explanation:
The formula is
1/a+1/b = 1/c where a and b are the times working along and c is the time working together
1/6 + 1/9 = 1/c
Multiply by 36c to clear the fractions
36c (1/6 + 1/9 = 1/c)
6c +4c = 36
10c = 36
Divide by 10
10c/10 = 36/10
c = 3.6 hours working together
Two numbers total 31 and have a difference of 11. Find the two numbers
Answer:
let 2 no. be x and y
x+y=31 ..... (1)
x-y=11 .........(2)
from (1)
x=31-y ..........(3)
putting (3) in (2)
31-y-y=11
-2y=11-31
-2y=-20
2y=20
y=10
Help! Please? Dont understand
which of the rolling equations have exactly one solutions ?
ps: (click the picture to see answer choices)
Answer:
All have exactly one solution
Step-by-step explanation:
a) -13x + 12 = 13x - 13
+13x +13x
-------------------------------
12 = 26x - 13
+13 +13
-------------------
25 = 26x
----- ------
26 26
25/26 = x
b) 12x + 12 = 13x - 12
-12x -12x
-----------------------
12 = x - 12
+12 +12
-----------------
24 = x
c) 12x + 12 = 13x + 12
-12x -12x
-----------------------------
12 = x + 12
0 = x
d) -13x + 12 = 13x + 13
+13x +13x
-----------------------------
12 = 26x + 13
-13 -13
-----------------------
-1 = 26x
--- -----
26 26
-1/26 = x
Find the length of the arc round your answer to the nearest 10th
Answer:
45
Step-by-step explanation:
The length of the arc is equal to the central angle it sees.
help with q25 please. Thanks.
First, I'll make f(x) = sin(px) + cos(px) because this expression shows up quite a lot, and such a substitution makes life a bit easier for us.
Let's apply the first derivative of this f(x) function.
[tex]f(x) = \sin(px)+\cos(px)\\\\f'(x) = \frac{d}{dx}[f(x)]\\\\f'(x) = \frac{d}{dx}[\sin(px)+\cos(px)]\\\\f'(x) = \frac{d}{dx}[\sin(px)]+\frac{d}{dx}[\cos(px)]\\\\f'(x) = p\cos(px)-p\sin(px)\\\\ f'(x) = p(\cos(px)-\sin(px))\\\\[/tex]
Now apply the derivative to that to get the second derivative
[tex]f''(x) = \frac{d}{dx}[f'(x)]\\\\f''(x) = \frac{d}{dx}[p(\cos(px)-\sin(px))]\\\\ f''(x) = p*\left(\frac{d}{dx}[\cos(px)]-\frac{d}{dx}[\sin(px)]\right)\\\\ f''(x) = p*\left(-p\sin(px)-p\cos(px)\right)\\\\ f''(x) = -p^2*\left(\sin(px)+\cos(px)\right)\\\\ f''(x) = -p^2*f(x)\\\\[/tex]
We can see that f '' (x) is just a scalar multiple of f(x). That multiple of course being -p^2.
Keep in mind that we haven't actually found dy/dx yet, or its second derivative counterpart either.
-----------------------------------
Let's compute dy/dx. We'll use f(x) as defined earlier.
[tex]y = \ln\left(\sin(px)+\cos(px)\right)\\\\y = \ln\left(f(x)\right)\\\\\frac{dy}{dx} = \frac{d}{dx}\left[y\right]\\\\\frac{dy}{dx} = \frac{d}{dx}\left[\ln\left(f(x)\right)\right]\\\\\frac{dy}{dx} = \frac{1}{f(x)}*\frac{d}{dx}\left[f(x)\right]\\\\\frac{dy}{dx} = \frac{f'(x)}{f(x)}\\\\[/tex]
Use the chain rule here.
There's no need to plug in the expressions f(x) or f ' (x) as you'll see in the last section below.
Now use the quotient rule to find the second derivative of y
[tex]\frac{d^2y}{dx^2} = \frac{d}{dx}\left[\frac{dy}{dx}\right]\\\\\frac{d^2y}{dx^2} = \frac{d}{dx}\left[\frac{f'(x)}{f(x)}\right]\\\\\frac{d^2y}{dx^2} = \frac{f''(x)*f(x)-f'(x)*f'(x)}{(f(x))^2}\\\\\frac{d^2y}{dx^2} = \frac{f''(x)*f(x)-(f'(x))^2}{(f(x))^2}\\\\[/tex]
If you need a refresher on the quotient rule, then
[tex]\frac{d}{dx}\left[\frac{P}{Q}\right] = \frac{P'*Q - P*Q'}{Q^2}\\\\[/tex]
where P and Q are functions of x.
-----------------------------------
This then means
[tex]\frac{d^2y}{dx^2} + \left(\frac{dy}{dx}\right)^2 + p^2\\\\\frac{f''(x)*f(x)-(f'(x))^2}{(f(x))^2} + \left(\frac{f'(x)}{f(x)}\right)^2 + p^2\\\\\frac{f''(x)*f(x)-(f'(x))^2}{(f(x))^2} +\frac{(f'(x))^2}{(f(x))^2} + p^2\\\\\frac{f''(x)*f(x)-(f'(x))^2+(f'(x))^2}{(f(x))^2} + p^2\\\\\frac{f''(x)*f(x)}{(f(x))^2} + p^2\\\\[/tex]
Note the cancellation of -(f ' (x))^2 with (f ' (x))^2
------------------------------------
Let's then replace f '' (x) with -p^2*f(x)
This allows us to form ( f(x) )^2 in the numerator to cancel out with the denominator.
[tex]\frac{f''(x)*f(x)}{(f(x))^2} + p^2\\\\\frac{-p^2*f(x)*f(x)}{(f(x))^2} + p^2\\\\\frac{-p^2*(f(x))^2}{(f(x))^2} + p^2\\\\-p^2 + p^2\\\\0\\\\[/tex]
So this concludes the proof that [tex]\frac{d^2y}{dx^2} + \left(\frac{dy}{dx}\right)^2 + p^2 = 0\\\\[/tex] when [tex]y = \ln\left(\sin(px)+\cos(px)\right)\\\\[/tex]
Side note: This is an example of showing that the given y function is a solution to the given second order linear differential equation.
I NEED HELP ASAP, I DON'T UNDERSTAND THIS PROBLEM!!!!!
Answer:
1
Step-by-step explanation:
Cosine is a trigonometric function that is represented by adjacent divided by the hypotenuse. The side adjacent to angle A is AC and the hypotenuse is AB, so we can say cos(A) = [tex]\frac{AC}{AB}[/tex]. We can do the same for angle B. The side adjacent to it is BC, and the hypotenuse is again AB. So, we can say
cos(B) = [tex]\frac{BC}{AB}[/tex]. We are solving for [tex]\frac{cosA}{cosB}[/tex], so we can substitute the value of those two and solve:
[tex]\frac{\frac{AC}{AB}}{\frac{BC}{AB} }[/tex]
[tex]\frac{AC}{AB} * \frac{AB}{BC} = \frac{AC}{BC}[/tex]
AC is given to be 3 and BC is also 3, so [tex]\frac{AC}{BC}[/tex] is [tex]\frac{3}{3}[/tex] which is just 1.
21. SCALE FACTOR A regular nonagon has an area of 90 square feet. A similar
nonagon has an area of 25 square feet. What is the ratio of the perimeters of
the first nonagon to the second?
Answer:
The ratio of the perimeters of the first nonagon to the second is 3.6 to 1.
Step-by-step explanation:
Given that a regular nonagon has an area of 90 square feet, and a similar nonagon has an area of 25 square feet, to determine what is the ratio of the perimeters of the first nonagon to the second, the following calculation must be performed:
25 = 1
90 = X
90/25 = X
3.6 = X
Therefore, the ratio of the perimeters of the first nonagon to the second is 3.6 to 1.
You pay $1.25 per pound for x pounds of apples?
Answer:
$1.25x
Step-by-step explanation:
Given :
Cost per pound = $1.25
Number of pounds of apple = x
The total cost of apple = (cost per pound * number of apple in pounds)
Hence,
Total cost of x pounds of apple is :
($1.25 * x)
= $1.25x
I want to know how to solve this equation
Answer:
your answer will be Option D
Step-by-step explanation:
log 10
A boat travels 400 kilometers in 9.6 hours (with a constant speed). How much time will it take to travel 138 kilometers? (round to the nearest tenth of an hour)
Step-by-step explanation:
here's the answer to your question
Graph the linear equation by find
2 = 4x + y
2=4x+y
y=2-4x
Александр Мазепов
Step-by-step explanation:
Step 1: Solve for y
[tex]2 = 4x + y[/tex]
[tex]2 - 4x = 4x + y - 4x[/tex]
[tex]y = 2 - 4x[/tex]
Step 2: Solve for x
[tex]2 - 2 - 4x = 0 - 2[/tex]
[tex]-4x / -4 = -2 / -4[/tex]
[tex]x = 1/2[/tex]
Step 3: Solve for y
[tex]y = 2 - 4(0)[/tex]
[tex]y = 2[/tex]
Step 4: Graph the equation
Graph the x-intercept, (1/2, 0), the y-intercept, (0, 2) and draw a line between them. Look at the attached picture for the graph:
Find the value of x and the value of y.
A. x = 4, y = 8
B.x=7, y=422
C. X= 4/3, y= 7.2
D. x= 73, y=412
Answer:
x = 7 and
y = 4[tex]\sqrt{2}[/tex]
Step-by-step explanation:
as you can see from the image we need to draw a line and when we do so we get a special right triangle with angle measures 90-45-45 and side lengths represented by a-a-a[tex]\sqrt{2}[/tex]
since the line we drew is parallel to the rectangle's length it's = 4 and so the number represented with a is also = 4
from there on we see x = 7 and y = 4[tex]\sqrt{2}[/tex]
Answer:
I can confirm, it is B! x=7 and y=4sqrt2
Step-by-step explanation:
edge
PLEASE HELPPPPP!!!! (answer in decimal)
Answer:
[tex]\approx 0.482659[/tex]
Step-by-step explanation:
The experimental probability is the chance of an event happening based on data, or rather the experiment results, and not on a theoretical calculation. In essence, a theoretical calculation can be described by the following formula:
[tex]\frac{desired}{total}[/tex]
However, the experimental probability can be described with the following formula:
[tex]\frac{number\ of\ desired\ outcomes}{number\ of \ trials}[/tex]
The number of trials is the sum of the number of outcomes. In this case, the desired outcome is tails. Therefore, the experimental probability can be described using the following formula:
[tex]\frac{tails}{total}[/tex]
One can also rewrite the formula as the following. This is because the total is the sum of the number of the two outcomes:
[tex]\frac{tails}{heads+tails}[/tex]
Substitute,
[tex]\frac{167}{167+179}[/tex]
Simplify,
[tex]\frac{167}{346}[/tex]
Rewrite as a decimal:
[tex]\approx 0.482659[/tex]
In the Data Analysis portion of the article the authors report that they completed a power analysis to determine the power of their study with the sample size utilized. They report a power of 90%. What does this mean
Answer:
Kindly check explanation
Step-by-step explanation:
The power of a test simply gives the probability of Rejecting the Null hypothesis, H0 in a statistical analysis given that the the alternative hypothesis, H1 for the study is true. Hence, the power of a test can be referred to as the probability of a true positive outcome in an experiment.
Using this definition, a power of 90% simply means that ; there is a 90% probability that the a Pvalue less Than the α - value of an experiment is obtained if there is truly a significant difference. Hence, a 90% chance of Rejecting the Null hypothesis if truly the alternative hypothesis is true.
A box of 8 marbles has 4 red, 2 green, and 2 blue marbles. If you select one marble, what is the probability that it is a red or blue marble.
Answer:
3/4
Step-by-step explanation:
add the no. of red marbles and blue marbles
2+4 = 6
Probability so divide 6/8 simplified to 3/4
Calculate the next term in the geometric sequence that is calculated with a ratio of 19 if the current term is 38
Answer:
Step-by-step explanation:
The next term is going to be simply 38*19 = 722
The series is geometric which means that you multiply from one term to get to the next.
The ratio of 19, and the current term is 38. So to get to the next term, multiply 38 * 19
A quality control expert at Glotech computers wants to test their new monitors. The production manager claims they have a mean life of 83 months with a variance of 81. If the claim is true, what is the probability that the mean monitor life would be greater than 81.2 months in a sample of 146 monitors? Round your answer to four decimal places.
Answer:
0.9922 = 99.22% probability that the mean monitor life would be greater than 81.2 months in a sample of 146 monitors.
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.
The production manager claims they have a mean life of 83 months with a variance of 81.
This means that [tex]\mu = 83, \sigma = \sqrt{81} = 9[/tex]
Sample of 146:
This means that [tex]n = 146, s = \frac{9}{\sqrt{146}}[/tex]
What is the probability that the mean monitor life would be greater than 81.2 months in a sample of 146 monitors?
This is 1 subtracted by the p-value of Z when X = 81.2. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{81.2 - 83}{\frac{9}{\sqrt{146}}}[/tex]
[tex]Z = -2.42[/tex]
[tex]Z = -2.42[/tex] has a p-value of 0.0078.
1 - 0.0078 = 0.9922.
0.9922 = 99.22% probability that the mean monitor life would be greater than 81.2 months in a sample of 146 monitors.
A researcher is interested in exploring the relationship between calcium intake and weight loss. Two different groups, each with 25 dieters, are chosen for the study.
Group A is required to follow a specific diet and exercise regimen, and also take a 500-mg supplement of calcium each day.
Group B is required to follow the same diet and exercise regimen, but with no supplemental calcium. After six months on the program, the members of Group A had lost a mean of 12.7 pounds with a standard deviation of 2.2 pounds. The members of Group B had lost a mean of 10.8 pounds with a standard deviation 2.0 pounds during the same time period. Assume that the population variances are not the same.
Create and interpret a 95% confidence interval to estimate the true difference between the mean amounts of weight lost by dieters who supplement with calcium and those who do not.
Answer:
(0.7044 ; 3.0956)
Step-by-step explanation:
Given:
GROUP A:
n1 = 25
x1 = 12.7
s1 = 2.2
GROUP B :
n2 = 25
x2 = 10.8
s2= 2.0
The obtain the confidence interval assuming unequal population variance :
(x1 - x2) ± tα/2[√(s1²/n1 + s2²/n2)]
The degree of freedom :
df = (s1²/n1 + s2²/n2)² ÷ (s1²/n1)²/n1-1 + (s2²/n2)²/n2-1
The degree of freedom :
(2.2²/25 + 2²/25)² ÷ (2.2²/25)²/24 + (2²/25)²/24
df = 0.12503296 ÷ (0.0015617 + 0.0010666)
df = 47.57 ;
df = 48
Tcritical value ; α = 95% ; df = 48
Tcritical = 2.0106
C.I = (12.7 - 10.8) ± 2.0106[√(2.2²/25 + 2²/25)]
C.I = 1.9 ± (2.0106 * 0.5946427)
C.I = 1.9 ± 1.1955887
C. I = (0.7044 ; 3.0956)
The length of a rectangle is 10 yd less than three times the width, and the area of the rectangle is 77 yd^2. Find the dimensions of the rectangle.
Answer:
W=7 and L=11
Step-by-step explanation:
We have two unknowns so we must create two equations.
First the problem states that length of a rectangle is 10 yd less than three times the width so: L= 3w-10
Next we are given the area so: L X W = 77
Then solve for the variable algebraically. It is just a system of equations.
3W^2 - 10W - 77 = 0
(3W + 11)(W - 7) = 0
W = -11/3 and/or W=7
Discard the negative solution as the width of the rectangle cannot be less then 0.
So W=7
Plug that into the first equation.
3(7)-10= 11 so L=11
can anybody help with this ?
Answer:(
fx).(gx)=D. -40x^3+25x^2+45
Step-by-step explanation:
For Coronado Industries, sales is $500000, variable expenses are $335000, and fixed expenses are $140000. Coronado’s contribution margin ratio is
a) 67%.
b) 33%.
c) 28%.
d) 5%.
A car travels 630 miles in 14 hours. At this rate, how far will it travel in 42 hours?
Assuming the car's speed [tex]\frac{630}{14}=45\mathrm{mph}[/tex] does not change, the car will travel [tex]45\cdot42=\boxed{1890}[/tex] miles.
Hope this helps :)
How much water do I need to add to l liters of pure alcohol to obtain a solution of 45% alcohol. Write as an expression.
Answer:
13/9l or 1 4/9 l
Step-by-step explanation:
Answer:
quantity of alcohol = l liters
we need to make a solution of having 45% alcohol by adding water.
45% alcohol means whatever id the total quantity of solution there is 45% alcohol.
Let the total quantity of solution be x.(
then
quantity of alcohol in terms of x = 45% of x = 45/100 x
but we know that quantity of alcohol = l liters
45/100 x = l
x = 100/45 l
Thus, total quantity of solution is 100/45 l,
but in it, there are l liters of alcohol.
to find the quantity of water we need to subtract the quantity of alcohol from the total quantity of solution
quantity of water in the solution = 100l/45 - l = (100l - 45l)/45 = 65l/45
quantity of water in the solution = 13/9l = 1 4/9 l -------->answer.
Thus, 1 4/9 liters of water needs to be added to l liters of alcohol to make a solution of 45% alcohol.
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