Answer:
a) 0.9544 = 95.44% of scores lie between 220 and 380 points.
b) 0.1587 = 15.87% probability that a randomly chosen student scores is below 260.
c) 25.14% of scores are above 326.8 points.
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.
Mean of 300 and a standard deviation of 40.
This means that [tex]\mu = 300, \sigma = 40[/tex]
(a) What proportion of scores lie between 220 and 380 points?
This is the p-value of Z when X = 380 subtracted by the p-value of Z when X = 220.
X = 380
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{380 - 300}{40}[/tex]
[tex]Z = 2[/tex]
[tex]Z = 2[/tex] has a p-value of 0.9772.
X = 220
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{220 - 300}{40}[/tex]
[tex]Z = -2[/tex]
[tex]Z = -2[/tex] has a p-value of 0.0228.
0.9772 - 0.0228 = 0.9544
0.9544 = 95.44% of scores lie between 220 and 380 points.
(b) What is the probability that a randomly chosen student scores is below 260?
This is the p-value of Z when X = 260. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{260 - 300}{40}[/tex]
[tex]Z = -1[/tex]
[tex]Z = -1[/tex] has a p-value of 0.1587.
0.1587 = 15.87% probability that a randomly chosen student scores is below 260.
(c) What percent of scores are above 326.8 points?
The proportion is 1 subtracted by the p-value of Z when X = 326.8. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{326.8 - 300}{40}[/tex]
[tex]Z = 0.67[/tex]
[tex]Z = 0.67[/tex] has a p-value of 0.7486.
1 - 0.7486 = 0.2514
0.2514*100% = 25.14%
25.14% of scores are above 326.8 points.
Which of the following graphs is described by the function given below?
y = x2 - 6x-7
Answer:
A
Step-by-step explanation:
We are given the function:
[tex]\displaystyle y = x^2 - 6x - 7[/tex]
And we want to determine its graph.
One of the most important features of a quadratic is its vertex. So, we can start by finding the vertex using the formulas:
[tex]\displaystyle \text{Vertex} = \left(-\frac{b}{2a}, f\left(-\frac{b}{2a}\right)\right)[/tex]
In this case, a = 1, b = -6, and c = -7.
Find the x-coordinate of the vertex:
[tex]\displaystyle x = -\frac{(-6)}{2(1)} = 3[/tex]
Substitute this back into the equation to find the y-coordinate:
[tex]\displaystyle y(3) = -16[/tex]
Therefore, our vertex is at (3, -16).
The only graph whose quadratic's vertex is at (3, -16) is Graph A. Thus, our answer is A.
A rectangular painting is to have a total area (including the frame) of 1200 cm2. If the painting is 30 cm long and 20 cm wide, find the width of the frame
Answer:
5 cm
Step-by-step explanation:
Let x = width of frame.
The width of the frame is added all around the painting, so you must add 2x to the length of the painting and 2x to the width of the painting to find the total length and width including the frame.
painting length: 30
total length: 2x + 30
painting width: 20
total width: 2x + 20
total area = LW
total area = (2x + 30)(2x + 20)
total area = 1200
(2x + 30)(2x + 20) = 1200
(x + 15)(x + 10) = 300
x^2 + 10x + 15x + 150 = 300
x^2 + 25x - 150 = 0
(x - 5)(x + 30) = 0
x - 5 = 0 or x + 30 = 0
x = 5 or x = -30
The width of the frame cannot be a negative number, so we discard the solution x = -30.
Answer: 5 cm
Find area and perimeter of shape but perimeter is not 96
Perimeter:
We have two straight, congruent sides from the square that are 24 cm, and two semi-circles (or one whole circle).
24 + 24 + 1/2(24pi) + 1/2(24pi)
48 + 12pi + 12pi
48 + 24pi cm
Area:
We have a semi-circle and a square that is missing a semi-circle. Let's find the area of the square minus the semi-circle, then add the additional semi-circle.
Square = 576
Missing semi-circle = 144pi / 2 = 72pi
Semi-circle = 144pi / 2 = 72pi
576 - 72pi + 72pi
576 cm^2
Hope this helps!
The cost of three pants and four shirts is $68.45 if a pant costs $6.85 more than a shirt find the cost of a pant and a shirt estimate to the nearest whole number.
Answer:
3 pants are $20.55
4 shirts are $47.9
Step-by-step explanation:
a pant is $6.85 × 3= $20.55
68.45 - 20.55 = $47.9
$47.9 ÷ 4 = $11.98 a shirt
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
There are 16 more people in front of Kollam on a line than behind him. There are five times as many people in front of him as behind him. How many people are on the line?
Answer:
There are 21 people in the line (including Kollam himself).
a cookie recipe calls 3 1/4 cups of flour. the recipe makes 3 dozen cookies. how much flour us needed to make 144 cookies
1 dozen = 12
144 / 12 = 12 dozen
12 dozen/ 3 = 4
They need 4 times the amount of flour:
3 1/4 x 4 = 13
They need 13 cups of flour
write your answer in simplest radical form
Answer:
[tex]s=6\sqrt{3}[/tex]
Step-by-step explanation:
In any 30-60-90 triangles, the sides are in ratio [tex]x:x\sqrt{3}:2x[/tex], where [tex]x[/tex] is the side opposite to the 30 degree angle and [tex]2x[/tex] is the hypotenuse of the triangle.
In the given diagram, the hypotenuse is marked as 12 miles. Therefore, the side opposite to the 30 degree angle must be [tex]12 \div 2=6[/tex] miles. The final leg, [tex]s[/tex], must then represent the [tex]x\sqrt{3}[/tex] part of our ratio, hence [tex]\implies \boxed{6\sqrt{3}}[/tex]
Find the slope and the y-intercept of the line with the given equation.
f(x) = 7 -4/5x
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The slope is
(Type an integer or a simplified fraction.)
B. The slope is undefined.
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The y-intercept is
(Simplify your answer. Type an ordered pair, using integers or fractions.)
B. There is no y-intercept.
Answer:
The slope is -4/5
The y intercept is (0,7)
Step-by-step explanation:
f(x) = 7 -4/5x
Rewriting
y = -4/5x +7
This is in slope intercept form
y = mx+b where m is the slope and x is the y intercept
The slope is -4/5
The y intercept is (0,7)
I need help please
Don’t skip the questions if you know the answer please I need the answers as soon as possible!!
y=x²-10x-7
a>0 so we will be looking for minimum
x=-b/2a=10/2=5
y=25-50-7=-32
Answer: (5;32)
y=-4x²-8x+1
а<0 so we will be looking for maximum
х=-b/2a=8/-8=-1
у=4+8+1=13
Maximum point (-1;13)
A semi-circle sits on top of a rectangle to form the figure below. Find its area and perimeter. Use 3.14 for .
4 in.
6 in.
O A = 38.13 square inches, P = 32.84 inches
O A = 80.52 square inches, P = 32.84 inches
O A = 38.13 square inches, P = 23.42 inches
O A = 80.52 square inches, P = 23.42 inches
9514 1404 393
Answer:
(c) A = 38.13 square inches; P = 23.42 inches
Step-by-step explanation:
The radius of the circle is half the diameter, so is 3 inches. This means the entire figure will fit in a rectangle 6 inches wide and 4+3 = 7 inches high. The perimeter of such a rectangle is ...
P = 2(L+W) = 2(7+6) = 26 inches
The area of that rectangle is ...
A = LW = (7)(6) = 42 square inches
Then area of the given figure is less than 42 square inches, and the perimeter is less than 26 inches. The only answer choice that matches these bounds is ...
A = 38.13 square inches; P = 23.42 inches
I need help with that, if you can, plz. I ty it I think is a not sure
Answer:
-5≤x <1
Step-by-step explanation:
sqrt( x+5) / sqrt(1-x)
The numerator must be greater than zero since it is a square root
sqrt(x+5) ≥0
Square each side
x+5≥0
x≥-5
The denominator must be greater than zero (the denominator cannot be zero)
sqrt(1-x)> 0
Square each side
1-x > 0
1>x
Putting these together
-5≤x <1
please help !!!!
i would really appreciate it
Answer: A
Step-by-step explanation: x=-2, y=3, z=-3
Answer:
A. -2, 3, -3
Step-by-step explanation:
x = 7 - 2y + z
y = 21 + 6x + 2z = 21 + 6×(7 - 2y + z) + 2z =
= 21 + 42 - 12y + 6z + 2z = 63 - 12y + 8z
13y = 63 + 8z
y = (63 + 8z)/13
2x + 2y - 3z = 11
2×(7 - 2y + z) + 2×(63 + 8z)/13 - 3z = 11
2×(7 - 2×(63 + 8z)/13 + z) + 2×(63 + 8z)/13 - 3z = 11
14 - 4×(63 + 8z)/13 + 2z + 2×(63 + 8z)/13 - 3z = 11
-2×(63 + 8z)/13 - z = -3
-2×(63 + 8z) - 13z = -39
-126 - 16z - 13z = -39
-29z = 87
z = -3
y = (63 + 8×-3)/13 = (63 - 24)/13 = 39/13 = 3
x = 7 - 2×3 + -3 = 7 - 6 - 3 = -2
Please help explanation need it
Step-by-step explanation:
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Write as an algebraic expression and simplify if possible: A number four more than 45% of d.
Answer:
0.45d + 4
Step-by-step explanation:
45% of d => 0.45d
Then a number 4 more is gonna be 0.45d + 4
The total amount of spending per year, in billions, on pets in a certain country x years after 2000 is given by the following function. P(x)=2.1786+25.2 a) Determine the total amount of spending per year on pets in 2007 and in 2012. b) Find and explain what it represents.
Answer:
40.4502 billion dollars
51.3432 billion dollars
Step-by-step explanation:
Given :
Total amount spent in billions in pets x years after year, 2000 ;
P(x)=2.1786x + 25.2
Amount spent in 2007 ;
x = 2007 - 2000 = 7 years
Put x = 7 in the equation :
P(7)=2.1786(7) + 25.2 = 40.4502
Amount spent in 2012 :
x = 2012 - 2000 = 12 years
Put x = 12 in the equation :
P(12) = 2.1786(12) + 25.2 = 51.3432
The amount spent in billik dollars on pets in :
2007 = $404502 billion
2012 = $51.3432 billion
155 ° 35 ° x °
x = ? °
x=35
vertical opposite angles are equal.
Which expression is equivalent to 5y^-3?
Answer:
5/y^3
Step-by-step explanation:
which expression is equivalent to 5y^-3
for example a^-1 = 1/a
5y^-3 = 5/y^3
please help, will give brainliest!!!!
Answer:
3
Step-by-step explanation:
3 - 3/x
----------------
1 - 1/x
Multiply the top and bottom by x
x(3 - 3/x)
----------------
x(1 - 1/x)
3x -3
------------
x-1
Factor the numerator
3(x-1)
-------
x-1
Cancel like terms
3
-----
1
3
Let f(x) = e ^3x/5x − 2. Find f'(0).
Answer:
Step-by-step explanation:
Our friend asking what the actual function is has a point. I completed this under the assumption that what we have is:
[tex]f(x)=\frac{e^{3x}}{5x-2}[/tex] and used the quotient rule to find the derivative, as follows:
[tex]f'(x)=\frac{e^{3x}(5)-[(5x-2)(3e^{3x})]}{(5x-2)^2}[/tex] and simplifying a bit:
[tex]f'(x)=\frac{5e^{3x}-[15xe^{3x}-6e^{3x}]}{(5x-2)^2}[/tex]and a bit more to:
[tex]f'(x)=\frac{5e^{3x}-15xe^{3x}+6e^{3x}}{(5x-2)^2}[/tex] and combining like terms:
[tex]f'(x)=\frac{11e^{3x}-15xe^{3x}}{(5x-2)^2}[/tex] and factor out the GFC in the numerator to get:
[tex]f'(x)=\frac{e^{3x}(11-15x)}{(5x-2)^2}[/tex] That's the derivative simplified. If we want f'(0), we sub in 0's for the x's in there and get the value of the derivative at x = 0:
[tex]f'(0)=\frac{e^0(11-15(0))}{(5(0)-2)^2}[/tex] which simplifies to
[tex]f'(0)=\frac{11}{4}[/tex] which translates to
The slope of the function is 11/4 at the point (0, -1/2)
ulwazi's Father offered to pay for Ani's wedding ring, which cost R1349 excluding 14%VAT calculate the selling price
9514 1404 393
Answer:
₹1537.86
Step-by-step explanation:
With the 14% tax added, the final cost is ...
₹1349 × (1 +14%) = ₹1349×1.14 = ₹1537.86
Write two ratios equivalent to 24 : 9.
Answer:
8:3
16:6
Step-by-step explanation:
First, let's check if 9 and 24 have any common factor. If they do have any common ones, we must find the GCF (greatest common factor).
Factors of 9: 1, 3, 9
Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24
The common factors both of the numbers share and 1 and 3. To find the GCF, simply compare one of the factors to the other.
1 < 3
Now that we know the GCF, we can divide the two numbers in the ratio 24 : 9 by it (3).
24:9
24/3:9/3
8:3
Now that our ratio is simplified, it's going to be much easier to find more ratios that are equivalent. 8:3 is already one equivalent ratio, but if we multiply each number in the ratio by any other number, we can get a new equivalent ratio. Let's multiply each number in the ratio by 2:
8:3
8 ⋅ 2:3 ⋅ 2
16:6
So, another equivalent ratio to 24:9 (and 8:3) is 16:6.
Write the equation of the line for a line that passes through (-2,-4) and (-1, -1).
Answer:
y = 3x+2
Step-by-step explanation:
First find the slope using the slope formula
m= (y2-y1)/(x2-x1)
= ( -1 - -4)/(-1 - -2)
= (-1 +4)/ (-1 +2)
= 3/1
= 3
The slope intercept formula is
y = mx+b where m is the slope and b is the y intercept
y = 3x+b
Using the point (-1,-1) and substituting into the equation
-1 = 3(-1)+b
-1 = -3+b
-1+3 = b
2 = b
y = 3x+2
Solve the inequality
Answer:
hope this helps buddy, please mark the brainliest.
Step-by-step explanation:
Find the equation of the line using the point-slope formula. Write the final equation using the slope-intercept form.
perpendicular to
7y = x − 4
and passes through the point
(−2, 1)
Answer:
[tex]y = -7x -13[/tex]
Step-by-step explanation:
Given
Perpendicular to
[tex]7y = x -4[/tex]
Passes through
[tex](-2,1)[/tex]
Required
The equation
First, we calculate the slope of:
[tex]7y = x -4[/tex]
Divide through by 7
[tex]y = \frac{1}{7}x - \frac{4}{7}[/tex]
A linear function is:
[tex]y=mx + c[/tex]
Where;
[tex]m \to slope[/tex]
So:
[tex]m = \frac{1}{7}[/tex]
For the perpendicular line; the slope is:
[tex]m_2 = -\frac{1}{m}[/tex]
So, we have:
[tex]m_2 = -\frac{1}{1/7}[/tex]
[tex]m_2 = -7[/tex]
The equation is:
[tex]y = m(x - x_1) + y_1[/tex]
So, we have:
[tex]y = -7(x - -2) + 1[/tex]
[tex]y = -7(x +2) + 1[/tex]
Open bracket
[tex]y = -7x -14 + 1[/tex]
[tex]y = -7x -13[/tex]
Explain how to multiply
the following
binomials
(2x - y)(2x + y).
Step-by-step explanation:
you can just use the punnet square method to multiply it
Use FOIL; first, outer, inner, last. Multiply the first terms in each binomial, the outer terms of each binomial, the inner terms of each binomial, and the last terms of each binomial. In this case, you multiply 2x*2x, 2x*y, -y*2x, and -y*y.
sold 72 books. if ratio of books to bookmarks is 9:2, how many bookmark was sold?
Answer:
16 bookmarks were sold
Answer:
40
Step-by-step explanation:
They sold 9 book marks for every 2 books (9:2 ratio).
72/9 = 2/x
Cross multiply. 72 * x = 72x
9 * 2 = 18
72 divided by 18 = 40
HELP NEEDED PLEASE :(
Identify the center and the radius of a circle that has a diameter with endpoints at (5, 8)
and (7,6).
Answer:
Centre is,
((5+7)/2,(8+6)/2)
or, (12/2,14/2)
or, (6,7)
radius is,
[√{(5-7)²+(8-6)²}]/2
= [√(2²+2²)]/2
= [√(4+4)]/2
= [√8 ]= [2√2]/2 = √2
The center of a circle = (6, 7)
the radius of a circle = [tex]\sqrt{2}[/tex] units
What is the distance formula?"The distance between two points [tex](x_1,y_1),(x_2,y_2)[/tex] is given by [tex]d=\sqrt{(x_2-x_1)^2+(y_2-y_2)^2}[/tex]"
What is midpoint formula?"The coordinates of the midpoint of the line segment having endpoints [tex](x_1,y_1),(x_2,y_2)[/tex] is given by [tex]m=(\frac{x_1+x_2}{2} ,\frac{y_1+y_2}{2} )[/tex] "
What is diameter of circle?"It is the line segment through the center and touching two points on its edge. "
For given question,
The diameter of circle has endpoints at (5, 8) and (7,6).
Let [tex](x_1,y_1)=(5,8),(x_2,y_2)=(7,6)[/tex]
First we find the length of the diameter of the circle.
Using the distance formula,
[tex]\Rightarrow d=\sqrt{(x_2-x_1)^2+(y_2-y_2)^2} \\\\\Rightarrow d=\sqrt{(7-5)^2+(6-8)^2} \\\\\Rightarrow d=\sqrt{2^2+(-2)^2}\\\\\Rightarrow d=\sqrt{4+4}\\\\\Rightarrow d=2\sqrt{2}~units[/tex]
We know that the diameter = 2 × radius
⇒ radius (r) = [tex]\frac{2\sqrt{2} }{2}[/tex]
⇒ r = [tex]\sqrt{2}[/tex] units
We know that the midpoint of the diameter is the center of the circle.
Using midpoint formula the center of the circle would be,
[tex]\Rightarrow O=(\frac{x_1+x_2}{2} ,\frac{y_1+y_2}{2} )\\\\\Rightarrow O=(\frac{5+7}{2} ,\frac{8+6}{2} )\\\\\Rightarrow O=(\frac{12}{2} ,\frac{14}{2} )\\\\\Rightarrow O=(6,7)[/tex]
Therefore, the center of the circle is (6,7)
Hence, the center of a circle = (6, 7)
the radius of a circle = [tex]\sqrt{2}[/tex]
Learn more about the distance formula and mid-point formula here:
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Write the equation of the line in fully simplified slope-intercept form.
Use the drop-down menu to create true statements,
If the graph of an inverse passes the
, you know that the inverse is
a function,
The composition of a function and its inverse is
always
DONE
DOWE
The range values of an inverse are the
values of the original function,
The graph of an inverse is the reflection of the
graph of the function over the line
DONE
DOWE
Answer:
A) Vertical test
B) y=x
C) x
D) domain
If the graph of an inverse passes the Vertical Line Test, you know that the inverse is a function.
What is Inverse Function?Inverse functions are functions which can be reversed in to another function.
Then the function is said to be the inverse of the second function.
The test which is used to know whether an inverse is a function or not is Vertical line Test.
So, if the graph of an inverse passes the Vertical Line Test, you know that the inverse is a function.
Composition of a function and it's inverse is always x.
Let y = f(x) be a function. Then x = f⁻¹ (y)
(f⁻¹of)(x) = f⁻¹ (f(x)) = f⁻¹ (y) = x
The graph of an inverse is the reflection of the graph of the function over the line y = x.
The range values of the inverse function are the domain values of the original function.
Hence the blank terms are found.
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