Answer:
Let r = amount of the 7% solution
y represent the amount of the 15 percent solution
r =7.5 L
y = 12.5 L
Step-by-step explanation:
Let r = amount of the 7% solution
y represent the amount of the 15 percent solution
.07r + .15 y = (r+y) .12
r+y = 20
y = 20-r
.07r + .15 (20-r) = (20) .12
0.07r+0.15(20-r)=2.4
.07r+ 3 - .15r = 2.4
-.08r = 2.4-3
-.08r = -.6
Divide by-.08
r =7.5
y = 20-7.5
y = 12.5
Suppose a rumor is going around a group of 191 people. Initially, only 38 members of the group have heard the rumor, but 3 days later 68 people have heard it. Using a logistic growth model, how many people are expected to have heard the rumor after 6 days total have passed since it was initially spread? (Round your answer to the nearest whole person.)
Answer:
106 people.
Step-by-step explanation:
Logistic equation:
The logistic equation is given by:
[tex]P(t) = \frac{K}{1+Ae^{-kt}}[/tex]
In which
[tex]A = \frac{K - P_0}{P_0}[/tex]
K is the carrying capacity, k is the growth/decay rate, t is the time and P_0 is the initial value.
Suppose a rumor is going around a group of 191 people. Initially, only 38 members of the group have heard the rumor.
This means that [tex]K = 191, P_0 = 38[/tex], so:
[tex]A = \frac{191 - 38}{38} = 4.03[/tex]
Then
[tex]P(t) = \frac{191}{1+4.03e^{-kt}}[/tex]
3 days later 68 people have heard it.
This means that [tex]P(3) = 68[/tex]. We use this to find k.
[tex]P(t) = \frac{191}{1+4.03e^{-kt}}[/tex]
[tex]68 = \frac{191}{1+4.03e^{-3k}}[/tex]
[tex]68 + 274.04e^{-3k} = 191[/tex]
[tex]e^{-3k} = \frac{191-68}{274.04}[/tex]
[tex]e^{-3k} = 0.4484[/tex]
[tex]\ln{e^{-3k}} = \ln{0.4484}[/tex]
[tex]-3k = \ln{0.4484}[/tex]
[tex]k = -\frac{\ln{0.4484}}{3}[/tex]
[tex]k = 0.2674[/tex]
Then
[tex]P(t) = \frac{191}{1+4.03e^{-0.2674t}}[/tex]
How many people are expected to have heard the rumor after 6 days total have passed since it was initially spread?
This is P(6). So
[tex]P(6) = \frac{191}{1+4.03e^{-0.2674*6}} = 105.52[/tex]
Rounding to the nearest whole number, 106 people.
The cost of producing a custom-made clock includes an initial set-up fee of $1,200 plus an additional $20 per unit made. Each clock sells for $60. Find the number of clocks that must be produced and sold for the costs to equal the revenue generated. (Enter a numerical value.)
Answer:
30 clocks
Step-by-step explanation:
Set up an equation:
Variable x = number of clocks
1200 + 20x = 60x
Isolate variable x:
1200 = 60x - 20x
1200 = 40x
Divide both sides by 40:
30 = x
Check your work:
1200 + 20(30) = 60(30)
1200 + 600 = 1800
1800 = 1800
Correct!
Using f(x)=2x+7 and g(x)=x-3, find f(g(-2))
Tara created a 1 inch cube out of paper.
1 in
If she doubles the volume of her cube, which statement could be true?
A Tara added two inches to the height, length and width of the cube.
B Tara added two inches to the height of the cube.
C Tara doubled the measurements of the cube's height, length and width.
D Tara doubled the measurement of the cube's height.
Answer:
answer D
Step-by-step explanation:
V=L*W*H=1 ==> L=1,W=1,H=1
A:
L-> L+2=1+2=3
W -> W+2 = 1+2=3
H -> H+2=1+2=3
V=3*3*3=27 not the doubled of the volume's cube
A is false
B:
H -> H+2=1+2=3
V=1*1*3=3 not the doubled of the volume's cube
B is false
C:
H -> 2*H=2*1=2
L -> 2*L=2*1=2
W -> 2*W = 2*1=2
V=2*2*2=8 not the doubled of the volume's cube
C is false
D:
H-> H*2=1*2=2
L=1
W=1
V=1*1*2=2 is the doubled of the volume's cube
D is true
If the cost of a 2.5 meter cloth is $30.5. What will be the cost of 22 meters ?
Answer:
268.40
Step-by-step explanation:
We can write a ratio to solve
2.5 meters 22 meters
----------------- = --------------
30.5 dollars x dollars
Using cross products
2.5 * x = 30.5 * 22
2.5x =671
Divide each side by 2.5
2.5x / 2.5 = 671/2.5
x =268.4
To make a committee 4 men are chosen out of 6 candidates. What is the probability that 2 certain people will serve on that committee
Answer:
The probability that 2 certain people will serve on that committee is 11.11%.
Step-by-step explanation:
Since to make a committee 4 men are chosen out of 6 candidates, to determine what is the probability that 2 certain people will serve on that committee the following calculation must be performed:
4/6 = 2/3
1/3 x 1/3 = X
0.333 x 0.333 = X
0.1111 = X
Therefore, the probability that 2 certain people will serve on that committee is 11.11%.
Answer:
[tex]\frac{2}{5}[/tex]
Step-by-step explanation:
6 groups, and 4 certain people
6
C
4
[tex]\frac{6!}{(6-2)!(2!)}[/tex]
1 × 2 × 3 × 4 × 5 × 6/1 × 2 × 3 × 4 × 1 × 2
1 × 2 × 3 × 4 × 5 × 6/1 × 2 × 3 × 4 × 1 × 2
5 × 6/ 1 × 2
30/2 = 15
15 possible combinations
4 people, and 2 specific ones
4
C
2
[tex]\frac{4!}{(4-2)!(2!)}[/tex]
1 × 2 × 3 × 4/1 × 2 × 1 × 2
1 × 2 × 3 × 4/1 × 2 × 1 × 2
12/2 = 6
[tex]\frac{6}{15}=\frac{\frac{6}{3} }{\frac{15}{3} } =\frac{2}{5}[/tex]
Suppose there are three balls in a box. On one of the balls is the number 1, on another is the number 2, and on the third is the number 3. You select two balls at random and without replacement from the box and note the two numbers observed. The sample space S consists of the three equally likely outcomes {(1, 2), (1, 3), (2, 3)} (disregarding order). Let X be the sum of the two balls selected. What is the mean of X
Step-by-step explanation:
a) X is a discrete uniform distribution. As the number of outcomes is only 3.
b) sum is at least 4
X ≥ 4--------
i.e (1,3) or (2,3)
probability of X ≥ 4 is 2/3
2/3= 0.667
66.7 % is the probability of the outcome to have a sum at least 4.
c) The 3 likely outcome of X
(1,2) where X ; 1+2=3
(1,3) where X ; 1+3=4
(2,3) where X ; 2+3=5
Mean = 3+4+5/ 3
Mean = 4
Feel free to ask any uncleared step
find and sketch the domain of the function. f(x,y)=√(4-x^2-y^2) +√(1-x^2)
Answer:
Hello
Step-by-step explanation:
The domain is limited with 2 lines parallel: -1 ≤ x ≤ 1
and the disk ? (inside of a circle) of center (0,0) and radius 2
[tex]dom\ f(x,y)=\{(x,y) \in \mathbb{R} ^2 | \ -1\leq x \leq -1\ and \ ( -\sqrt{4-x^2} \leq \ y \leq \sqrt{4-x^2}\ ) \ \}\\[/tex]
The mode of 3 numbers is 6 and the
range is 4. Write down a possible set of
numbers.
Answer:
solution,
mode of 3 numbers is 6
range is 4
possible set of numbers are
{3,4,6,{} }
Which graph represents a line with a slope of -2/3 and a y-intercept equal to that of the line y=2/3x - 2
Answer: The image shown in your question as well as the one I provided is the correct answer
Step-by-step explanation:
a line with a slope of 2/3 must mean that the "m" is 2/3
y = mx + b
y = 2/3x + b
The question calls for the y-intercept to be equal to that of y=2/3x - 2
using the given equation, we easily figure out -2 is the y-intercept
so the line must go through (0,-2).
Anthony read 46 pages of a book in 23 minutes.
To find the unit rate, use
.
Anthony read
pages per minute.
Answer:
2 pages per minute
Step-by-step explanation:
Take the number of pages and divide by the number of minutes
46 pages / 23 minutes
2 pages per minute
2 Pages per Minute
Solutions:46 ÷ 23 = 2
Final Answer:Anthony can read 2 pages per minute.
At the Fidelity Credit Union, a mean of 3.5 customers arrive hourly at the drive-through window. What is the probability that, in any hour, more than 5 customers will arrive? Round your answer to four decimal places.
Answer:
0.1423 = 14.23% probability that, in any hour, more than 5 customers will arrive.
Step-by-step explanation:
We have the mean, which means that the Poisson distribution is used to solve this question.
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:
[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]
In which
x is the number of sucesses
e = 2.71828 is the Euler number
[tex]\mu[/tex] is the mean in the given interval.
A mean of 3.5 customers arrive hourly at the drive-through window.
This means that [tex]\mu = 3.5[/tex]
What is the probability that, in any hour, more than 5 customers will arrive?
This is:
[tex]P(X > 5) = 1 - P(X \leq 5)[/tex]
In which
[tex]P(X \leq 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)[/tex]
Then
[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]
[tex]P(X = 0) = \frac{e^{-3.5}*3.5^{0}}{(0)!} = 0.0302[/tex]
[tex]P(X = 1) = \frac{e^{-3.5}*3.5^{1}}{(1)!} = 0.1057[/tex]
[tex]P(X = 2) = \frac{e^{-3.5}*3.5^{2}}{(2)!} = 0.1850[/tex]
[tex]P(X = 3) = \frac{e^{-3.5}*3.5^{3}}{(3)!} = 0.2158[/tex]
[tex]P(X = 4) = \frac{e^{-3.5}*3.5^{4}}{(4)!} = 0.1888[/tex]
[tex]P(X = 5) = \frac{e^{-3.5}*3.5^{5}}{(5)!} = 0.1322[/tex]
Finally
[tex]P(X \leq 5) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.0302 + 0.1057 + 0.1850 + 0.2158 + 0.1888 + 0.1322 = 0.8577[/tex]
[tex]P(X > 5) = 1 - P(X \leq 5) = 1 - 0.8577 = 0.1423[/tex]
0.1423 = 14.23% probability that, in any hour, more than 5 customers will arrive.
A random sample of medical files is used to estimate the proportion p of all people who have blood type B. (a) If you have no pre-liminary estimate for p, how many medical files should you include in a random sample in order to be 90% sure that the point estimate will be within a distance of 0.03 from p?(b) Answer part (a) if you use the pre-liminary estimate that about 13 out of 90 people have blood type B.
Answer:
a) 752 medical files should be included.
b) 372 medical files should be included.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.
[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
In which
z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].
The margin of error is of:
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
90% confidence level
So [tex]\alpha = 0.1[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.1}{2} = 0.95[/tex], so [tex]Z = 1.645[/tex].
Question a:
This is n for which M = 0.03. We have no estimate, so we use [tex]\pi = 0.5[/tex]. So
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
[tex]0.03 = 1.645\sqrt{\frac{0.5*0.5}{n}}[/tex]
[tex]0.03\sqrt{n} = 1.645*0.5[/tex]
[tex]\sqrt{n} = \frac{1.645*0.5}{0.03}[/tex]
[tex](\sqrt{n})^2 = (\frac{1.645*0.5}{0.03})^2[/tex]
[tex]n = 751.67[/tex]
Rounding up:
752 medical files should be included.
Question b:
Now we have that:
[tex]\pi = \frac{13}{90} = 0.1444[/tex]
So
[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]
[tex]0.03 = 1.645\sqrt{\frac{0.1444*0.8556}{n}}[/tex]
[tex]0.03\sqrt{n} = 1.645\sqrt{0.1444*0.8556}[/tex]
[tex]\sqrt{n} = \frac{1.645\sqrt{0.1444*0.8556}}{0.03}[/tex]
[tex](\sqrt{n})^2 = (\frac{1.645\sqrt{0.1444*0.8556}}{0.03})^2[/tex]
[tex]n = 371.5[/tex]
Rounding up:
372 medical files should be included.
HELP ASAP PLEASE! I tried inputting the numbers into the standard deviation equation but I did not get the right answer to find z. Can someone please help me? Thank you for your time!
Answer:
Z = -1.60
it is low ... it appears that for this problem 2 standard deviations below must be reached to be considered "unusual"
Step-by-step explanation:
the adjacent sides of a parallelogram are (x + 3) and (x + 2). Find the perimeter of the parallelogram
9514 1404 393
Answer:
4x+10
Step-by-step explanation:
For parallelogram adjacent sides a and b, the perimeter is ...
P = 2(a +b)
For the given sides, the perimeter is ...
P = 2((x +3) +(x +2)) = 2(2x +5)
P = 4x +10 . . . perimeter of the parallelogram
Simplify this expression 3^-3
ASAPPPP PLSSSS
Step-by-step explanation:
-27 okay 3^-3 its same as 3^3
Answer: A)
[tex]3^{-3}[/tex]
[tex]3^{-3}=\frac{1}{3^3}[/tex]
[tex]=\frac{1}{3^3}[/tex]
[tex]3^3=27[/tex]
[tex]=\frac{1}{27}[/tex]
OAmalOHopeO
How many subsets of at least one element does a set of seven elements have?
[tex]\boxed{\large{\bold{\blue{ANSWER~:) }}}}[/tex]
For each subset it can either contain or not contain an element. For each element, there are 2 possibilities. Multiplying these together we get 27 or 128 subsets. For generalisation the total number of subsets of a set containing n elements is 2 to the power n.
total subsets
2^n2⁷128A wire 9 meters long is cut into two pieces. One piece is bent into a equilateral triangle for a frame for a stained glass ornament, while the other piece is bent into a circle for a TV antenna. To reduce storage space, where should the wire be cut to minimize the total area of both figures? Give the length of wire used for each: For the equilateral triangle:
The length of wire used for the equilateral triangle is approximately 5.61 meters.
The remaining length of wire used for the circle will be 9 - 5.61 ≈ 3.39 meters.
Here,
To minimize the total area of both figures, we need to find the optimal cut point for the wire.
Let's assume the length of the wire used for the equilateral triangle is x meters, and the remaining length of the wire used for the circle is (9 - x) meters.
For the equilateral triangle:
An equilateral triangle has all three sides equal in length.
Let's call each side of the triangle s meters. Since the total length of the wire is x meters, each side will be x/3 meters.
The formula to find the area of an equilateral triangle with side length s is:
Area = (√(3)/4) * s²
Substitute s = x/3 into the area formula:
Area = (√(3)/4) * (x/3)²
Area = (√(3)/4) * (x²/9)
Now, for the circle:
The circumference (perimeter) of a circle is given by the formula:
Circumference = 2 * π * r
Since the remaining length of wire is (9 - x) meters, the circumference of the circle will be 2π(9 - x) meters.
The formula to find the area of a circle with radius r is:
Area = π * r²
To find the area of the circle, we need to find the radius.
Since the circumference is equal to 2πr, we can set up the equation:
2πr = 2π(9 - x)
Now, solve for r:
r = (9 - x)
Now, substitute r = (9 - x) into the area formula for the circle:
Area = π * (9 - x)²
Now, we want to minimize the total area, which is the sum of the areas of the triangle and the circle:
Total Area = (√(3)/4) * (x²/9) + π * (9 - x)²
To find the optimal value of x that minimizes the total area, we can take the derivative of the total area with respect to x, set it to zero, and solve for x.
d(Total Area)/dx = 0
Now, find the critical points and determine which one yields the minimum area.
Taking the derivative and setting it to zero:
d(Total Area)/dx = (√(3)/4) * (2x/9) - 2π * (9 - x)
Setting it to zero:
(√(3)/4) * (2x/9) - 2π * (9 - x) = 0
Now, solve for x:
(√(3)/4) * (2x/9) = 2π * (9 - x)
x/9 = (8π - 2πx) / (√(3))
Now, isolate x:
x = 9 * (8π - 2πx) / (√(3))
x(√(3)) = 9 * (8π - 2πx)
x(√(3) + 2π) = 9 * 8π
x = (9 * 8π) / (√(3) + 2π)
Now, we can calculate the value of x:
x ≈ 5.61 meters
So, the length of wire used for the equilateral triangle is approximately 5.61 meters.
The remaining length of wire used for the circle will be 9 - 5.61 ≈ 3.39 meters.
To learn more on derivative click:
brainly.com/question/12445967
#SPJ4
Which property was used to simplify the expression 4(b+2)=4b+8
Answer: distributive property
Step-by-step explanation: the 4 is multiplied by everting in the parenthesis
A chemist has three different acid solutions.
The first solution contains 25% acid, the second contains 35%acid, and the third contains 55% acid.
She created 120 liters of a 40% acid mixture, using all three solutions. The number of liters of 55% solution used is 3 times the number of liters of 35% solution used.
How many liters of each solution was used?
Let x, y, and z be the amounts (in liters, L) of the 25%, 35%, and 55% solutions that the chemist used.
She ended up with 120 L of solution, so
x + y + z = 120 … … … [1]
x L of 25% acid solution contains 0.25x L of acid. Similarly, y L of 35% solution contains 0.35y L of acid, and z L of 55% solution contains 0.55z L of acid. The concentration of the new solution is 40%, so that it contains 0.40 (120 L) = 48 L of acid, which means
0.25x + 0.35y + 0.55z = 48 … … … [2]
Lastly,
z = 3y … … … [3]
since the chemist used 3 times as much of the 55% solution as she did the 35% solution.
Substitute equation [3] into equations [1] and [2] to eliminate z :
x + y + 3y = 120
x + 4y = 120 … … … [4]
0.25x + 0.35y + 0.55 (3y) = 48
0.25x + 2y = 48 … … … [5]
Multiply through equation [5] by -2 and add that to [4] to eliminate y and solve for x :
(x + 4y) - 2 (0.25x + 2y) = 120 - 2 (48)
0.5x = 24
x = 48
Solve for y :
x + 4y = 120
4y = 72
y = 18
Solve for z :
z = 3y
z = 54
On a coordinate plane, a curved line begins at point (negative 2, negative 3), crosses the y-axis at (0, negative .25), and the x-axis at (1, 0).
What is the domain of the function on the graph?
Answer:
Option D
Step-by-step explanation:
correct answer on edge :)
Answer:
D <3
Step-by-step explanation:
Please help with this question
9514 1404 393
Answer:
(d) -1/32
Step-by-step explanation:
It may be easier to rearrange the expression so it has positive exponents.
[tex]\dfrac{1}{2^{-2}x^{-3}y^5}=\dfrac{2^2x^3}{y^5}=\dfrac{4(2)^3}{(-4)^5}=-\dfrac{4\cdot8}{1024}=\boxed{-\dfrac{1}{32}}[/tex]
A bus driver makes roughly $3280 every month. How much does he make in one week at this rate.
Answer:
I think around $36
Hope it helps!
Answer:
It depends...
Step-by-step explanation:
It depends how much weeks are in the month if there are three weeks and no extra days then you would have an answer of about 1093 (exact: 1093.33333333). just divide the number of weeks by the number of money.
Question 4 of 10
If A = (-1,-3) and B = (11,-8), what is the length of AB?
A. 12 units
B. 11 units
C. 14 units
D. 13 units
SUBMIT
Step-by-step explanation:
AB = square root of [(xA-xB)^2+(yA-yB)^2]
AB=Squarerootof(-1-11)^2 +(-3-(-8))^2=Squarerootof(-12)^2+(5)^2)
AB=Squarerootof((144)+25)= Squarerootof(169)=13 the answer is 13 units
The choice D is the right one
Which point is a solution to y equal greater than or less too
4x + 5?
Answer:
4x+ 4
Step-by-step explanation:
Please help with this question
Answer:
im not too sure but try using a cartesuan plane and measure it precisely using a protractor then key in the measurements. Im not entirely sure its the correct method tho
Suppose the method of tree ring dating gave the following dates A.D. for an archaeological excavation site. Assume that the population of x values has an approximately normal distribution.
1241 1210 1267 1314 1211 1299 1246 1280 1291
a. Determine if the data meets the initial conditions to construct a confidence interval.
b. Find the sample mean year x and sample standard deviation σ.
c. What is the maximal margin of error when finding a 90 % confidence interval for the mean of all tree-ring dates from this archaeological site?
Answer:
(1238.845 ;1285.376)
Step-by-step explanation:
Conditions for constructing a confidence interval :
Data must be random
Distribution should be normal and independent ;
Based on the conditions above ; data meets initial conditions ;
C. I = sample mean ± margin of error
Given the data :
1241 1210 1267 1314 1211 1299 1246 1280 1291
Mean, xbar = Σx / n = 11359 / 9 = 1262.11
The standard deviation, s = [√Σ(x - xbar)²/n - 1]
Using a calculator ; s = 37.525
The confidence interval :
C.I = xbar ± [Tcritical * s/√n]
Tcritical(0.10 ; df = n - 1 = 9 - 1 = 8)
Tcritical at 90% = 1.860
C. I = 1262.11 ± [1.860 * 37.525/√9]
C.I = 1262.11 ± 23.266
(1238.845 ;1285.376)
± 23.266
The margin of error :
[Tcritical * s/√n]
[1.860 * 37.525/√9]
C.I = ± 23.266
[(2021-Y)-5]*X-X=XX cho biết X,Y,XX là gì?
Help on this math question please
Answer:
3x² + x + 1
-3x² + x + 1
-54
Step-by-step explanation:
there is nothing complicated to it. you just use the requested pertain on the whole expressions of the functions, and the result is then the new function.
so,
r(x) = 3x²
s(x) = x + 1
what do you think s + r is ?
it is simply
(s+r)(x) = 3x² + x + 1
done. that is really all there is to this.
now the next (but consider the sequence due to the sign)
(s-r)(x) = x + 1 - 3x² = -3x² + x + 1
and the third
(s×r)(x) = 3x²(x+1) = 3x³ + 3x²
so, for x=-3
(s×r)(-3) = 3×(-3)³ + 3×(-3)²
remember, an even power of a negative number gives a positive result, an uneven power of a negative number gives a negative result.
(s×r)(x) = 3×-27 + 3×9 = -81 + 27 = -54
i need help. i will give brainiest as soon as possible
Answer:
B
Step-by-step explanation:
Let me know if you need an explanation.
Answer:
B
Step-by-step explanation:
4x^3+x^2+5x+2
4x^3 cannot cancel with others= 4x^3
4x^2-3x^2= x^2
5x cannot cancel with others= 5x
-3+5= 2
4x^3+x^2+5x+2
