The rocks are chosen without replacement, which means that the hypergeometric distribution is used to solve this question. First we get the parameters, and then we answer the questions. From this, we get that:
[tex]E(X) = 5.25, Var(X) = 0.5966[/tex]P(X < 6) = 0.9545P(all specimens of one of the two types of rock are selected for analysis) = 0.2046.Hypergeometric distribution:
The probability of x successes is given by the following formula:
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
In which:
x is the number of successes.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.
Combinations formula:
[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
The mean and the variance are:
[tex]\mu = \frac{nk}{N}[/tex]
[tex]\sigma^2 = \frac{nk(N-k)(N-n)}{N^2(N-1)}[/tex]
We have that:
5 + 7 = 12 rocks, which means that [tex]N = 12[/tex]
9 are chosen, which means that [tex]n = 9[/tex]
7 are granite, which means that [tex]k = 7[/tex]
Question a:
[tex]E(X) = \mu = \frac{9\times7}{12} = 5.25[/tex]
[tex]Var(X) = \sigma^2 = \frac{9\times7(12-7)(12-9)}{12^2(12-1)} = 0.5966[/tex]
Thus:
[tex]E(X) = 5.25, Var(X) = 0.5966[/tex]
Question b:
Since there are only 5 specimens of basaltic rock, at least 9 - 5 = 4 specimens of granite are needed, which means that:
[tex]P(X < 6) = P(X = 4) + P(X = 5) + P(X = 6)[/tex]
In which
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
[tex]P(X = 4) = h(4,12,9,7) = \frac{C_{7,4}*C_{5,5}}{C_{12,9}} = 0.1591[/tex]
[tex]P(X = 5) = h(5,12,9,7) = \frac{C_{7,5}*C_{5,4}}{C_{12,9}} = 0.4773[/tex]
[tex]P(X = 6) = h(6,12,9,7) = \frac{C_{7,6}*C_{5,3}}{C_{12,9}} = 0.3181[/tex]
Thus
[tex]P(X < 6) = P(X = 4) + P(X = 5) + P(X = 6) = 0.1591 + 0.4773 + 0.3181 = 0.9545[/tex]
So P(X < 6) = 0.9545.
Question c:
5 of basaltic and 4 of granite: 0.1591 probability.
7 of granite is P(X = 7), in which
[tex]P(X = 7) = h(7,12,9,7) = \frac{C_{7,7}*C_{5,2}}{C_{12,9}} = 0.0455[/tex]
0.1591 + 0.0455 = 0.2046, thus:
P(all specimens of one of the two types of rock are selected for analysis) = 0.2046.
A similar question is found at https://brainly.com/question/24008577
Solve the system of equations.
3x + 4y + 3z = 5
2x + 2y + 3z = 5
5x+ 6y+7z = 7
a. (x = 13, y=-6, z = -2)
b. (x = 15, y = -8, z = -4)
c. (x = 16, y = -9, z = -1)
d. (x = 14, y = -7, z = 3)
Answer:
x = 14
y = -7
z = -3
but this is none of the provided answer options !
Step-by-step explanation:
it's really easy by principle. it's just some work to do.
we try to find equations to express one variable in terms of the others.
but one thing there is : your teacher made a mistake.
the right solution is x = 14, y = -7, z = -3
your teacher made a typo at d.
but the right answer should be d.
just to give you an idea how this can be done (and also to prove that there is a mistake by the teacher):
we can directly try to transform one expression into one that describes x by y and z.
and then another to describe e.g. z by y. and then solve the third one just for y. and then we get the other 2 by these other expressions.
or we can e.g. add or subtract one equation to/from another. this is one of these cases, because we can find really simple expressions that way :
we do
5x + 6y + 7z = 7
- (3x + 4y + 3z = 5)
- (2x + 2y + 3z = 5)
---------------------------
0x + 0y + z = -3
=> z = -3
3x + 4y - 3×3 = 5
3x = -4y + 14
x = (-4y + 14)/3
2×(-4y + 14)/3 + 2y - 9 = 5
(-8y + 28)/3 + 2y = 14
-8y + 28 + 6y = 42
-2y = 14
y = -7
x = (-4×-7 + 14)/3 = (28+14)/3 = 42/3 = 14
If there are g girls and b-boys in a room, write an expression for the total number of children in the room.
Answer:
g+b
number of girls+number of boys
if i am incorrect forgive me plz
The expression for the total number of children in a room is g+ b.
What is an expression?
Expressions in math are mathematical statements that have a minimum of two terms containing numbers or variables, or both, connected by an operator in between.
What is addition?Addition is the process of finding the total, or sum, by combining two or more numbers or variables.
According to the given question
We have
Number of girls = g
And, number of boys = b
Therefore, the expression for the total number of children in room is given by
Total number of children = g + b
Hence, the expression for the total number of children in a room is g+ b.
Learn more about expression and addition here:
https://brainly.com/question/10386370
#SPJ2
what is the scale of factor?
The length of CV is 5 units
The length of C’V’ is 7.5 units
The scale factor is 7.5 / 5 = 1.5
Answer: 1.5
The cost of producing x units of a particular commodity is 2 C(x) = x' +6x +45 shillings, and the production level t hours into a particular production run is x(1)=0.312 +0.04 units. At what rate is cost changing with respect to time after 5 hours?
Complete question is;
The cost of producing x units of a particular commodity is C(x) = ⅔x² + 6x + 45 shillings and the production level t hours into a particular production run is x(t) = 0.3t² + 0.04t. At what rate is cost changing with respect to time after 5 hours?
Answer:
dC/dt = 49.45
Step-by-step explanation:
Since C(x) = ⅔x² + 6x + 45
And x(t) = 0.3t² + 0.04t
This means that;
C(x) = C(x(t))
The rate at what cost is changing with respect to time is given as;
dC/dt
Thus, from chain rule;
dC/dt = (dC/dx) × (dx/dt)
dC/dx = (4/3)x + 6
dx/dt = 0.6t + 0.04
Now, when t = 5, then;
x(5) = 0.3(5)² + 0.04(5)
x = 7.7
Thus;
dC/dx = (4/3)x + 6 = (4/3)(7.7) + 6 = 16.267
At 5 hours,
dx/dt = 0.6(5) + 0.04 = 3.04
Thus;
dC/dt = 16.267 × 3.04
dC/dt = 49.45
A sample of 38 babies in the zinc group had a mean birth weight of 3328 grams. A sample of 31 babies in the placebo group had a mean birth weight of 3406 grams. Assume that the population standard deviation for the zinc group is 640 grams, while the population standard deviation for the placebo group is 851851 grams. Determine the 99% confidence interval for the true difference between the mean birth weights for "zinc" babies versus "placebo" babies.
Required:
Find the point estimate for the true difference between the population means.
Answer:
-78
Step-by-step explanation:
Zinc group :
Mean, x1 = 3328
σ1 = 640
Sample size, n1 = 28
Placebo group :
Mean, x2 = 3406
σ2 = 851
Sample size, n2 = 31
The point estimate for the true difference between the population means is obtained as :
Mean difference between population :
x1 - x2 = 3328 - 3406 = - 78
PLEASE HELP!!
Indicate the method you would use to prove the two ▵‘s ≅. If no method applies, enter “none”
A. SSS
B. SAS
C. ASA
D. AAS
E. None
(I attached the triangle thing that goes with the question)
Sandra ride her bike 5 times as many miles as Barbara. If b, the distance Barbara rode equals 3.4 miles what is the correct expression and the distance Sandra rode
Answer:
b + 5; when b = 3.4 the distance Sandra rode is 17 miles.
Step-by-step explanation:
Suppose (-13,2) is a point on the graph of y=f(x). What is a point that will be on the graph of y=9f(x)-5
9514 1404 393
Answer:
(x, y') = (-13, 13)
Step-by-step explanation:
At the given value of x, f(x) = 2. Then 9f(x)-5 = 9(2) -5 = 13.
The point on the scaled, translated graph will be ...
(x, y') = (-13, 13)
_____
The graph shows a function f(x) with a distinct feature (vertex) at (-13, 2). It also shows where that distinct feature moves to when the function is scaled and translated.
A school sports team contains 68 students. 33 do field events, 40 do track events, 23 do swimming, 14 do both field and track events, 8 do both swimming and field events. If 15 students do field events only and 10 do both swimming and track events, how many students do a. Swimming only b. Track events only c. All three events?
Answer:
a. 9 students
b. 20 students
c. 4 students
What are the coordinates of point S"?
Answer:
point s: (-2,6)
-2 is the x coordinate
6 is the y coordinate
Laura made $273 for 13 hours of work.
At the same rate, how much would she make for 17 hours of work?
sl
X
$
?
I
Natalie's team needs to make a decision on how to handle a big product recall. People on the team have a lot of strong opinions. Management wants everyone to come to a consensus and to find a solution that everyone can support. What's the best way to get to a consensus? a) Everyone on the team talks until the entire team agrees on one decision. O b) Everyone on the team discusses options and then votes. O c) The team passes the decision-making responsibility to an outside person. O di The team leader makes a decision without input from the other members.
HELP PLEASEEEE!!!! ASAP
Answer:
6.22 sec
Step-by-step explanation:
h(t) = 105t-16t^2
For values of t for which height will be 34 feet can be obtained by substituting 34 in place of h(t) and solving for t
34=105t-16t^2, using quadratic formula we have t=1/32*(105±sqrt(8849)) which translates to - 0.34sec and 6.22sec but as time can't be negative, time is 6.22sec
(1+y²)dx + (1+x²)dy = 0
This differential equation is separable:
(1 + y²) dx + (1 + x²) dy = 0
(1 + y²) dx = - (1 + x²) dy
dy/(1 + y²) = -dx/(1 + x²)
Integrating both sides gives
arctan(y) = -arctan(x) + C
and solving for y gives (over an appropriate domain)
y = tan(C - arctan(x))
(the domain being -1 ≤ y ≤ 1).
Find the fraction equivalent to 5/7 with: a) numerator 25 b) denominator 42
Answer:
a) 25/35
b) 30/42
Step-by-step explanation:
a)
Variable x = denominator if numerator is 25
5/7 = 25/x
5 × x = 7 × 25
5x = 175
x = 35
b)
Variable y = numerator if denominator is 42
5/7 = y/42
5 × 42 = 7 × y
210 = 7y
30 = y
25/35
30/42
To get 25/35 multiply by 5
To get 30/42 multiply by 6
10x^3 - 25x^2 + 20
How to factor this
5(2x^2-x-2)(x-2)
Step-by-step
Answer: [tex]5(\frac{10x^3}{5}+\frac{-25x^2}{5}+\frac{20}{5}) \\\\5(2x^3-5x^2+4)\\\\5(2x^2-x-2)(x-2)[/tex]
The seventh-grade class is raising money
to have a class trip at the end of the year.
They began the year with $1,500. Now they
have $1,650 in the account.
What is the percent of increase for the
money the class has raised? I
a.
b.
Make Sense and Persevere The
class figured out that if the percent
increase is 99% from the beginning of
the year, the class will have enough
money for every student to go on the
field trip. How much money will the
class need to raise for every student to
go.
Answer:
The percent of the increase for the money the class raised is 10 %
Step-by-step explanation:
Because if you divide 1500 by 10 you get 150 that means 150 is 10 % of 1500 and if you add 150 to 1500 you get 1650 so the increase of money the class raised is 10 %
A line passes through the point (-3, -3) and has a slope of 1/2 What is the equation of the line?
Answer:
y= 1/2x-3/2
Step-by-step explanation:
The slope intercept form of a line is
y = mx+b where m is the slope and b is the y intercept
y = 1/2x+b
Using the point for x and y we can find b
-3 = 1/2(-3)+b
-3 = -3/2 +b
-6/2 = -3/2+b
Add 3/2 to each side
-6/2 +3/2 = b
-3/2 = b
y= 1/2x-3/2
Answer:
Step-by-step explanation:
y + 3 = 1/2(x + 3)
y + 3 = 1/2x + 3/2
y + 6/2 = 1/2x + 3/2
y = 1/2x - 3/2
Hal's business made $500,000 last year. This year, his business made $650,000. What is the percentage difference? [?]%
Answer:
the answer is 30 percent.
Step-by-step explanation:
i did it on acellus.
PLEASE HELP ASAP!!! (answer in decimal)
Answer:
re send it
Step-by-step explanation:
ty
Write the following as an expression: How much water do I need to add to l liters of pure alcohol to obtain a solution of 45% alcohol? The answer is an EXPRESSION, not an actual answer!! WILL MARK BRAINLIST!!!
Answer:
see below
Step-by-step explanation:
amount of water w
l liter of pure alcohol = 100% alcohol
solution is 45 % percent alcohol
total amount of fluid is w+l
(w+l)( .45) = l*.100
Distribute
.45w + .45 l = 1l
.45 w = 1l - .45l
.45 w = .55l
w = .55l / .45
w =11/9 l
A^2 + 2AB +B^2
habsbsjabdhjsbfhjbsdjh
If the slope of a wheelchair ramp is 1/11 then what is the angle of inclination to the nearest tenth of a degree?
Answer
4.8 degrees to the nearest tenth.
Step-by-step explanation:
The slope = rise / run = opposite side / adjacent side.
So the angle of inclination is the angle whose tangent is 1/12.
To the nearest tenth of a degree it is 4.8 degrees.
What inequality symbol belongs in the circle: -4 _ 5
30 POINTS!
Answer:
<
Step-by-step explanation:
Inequality symbols:
< less than
> greater than
= equal to
≤ less than or equal to
≥ greater than or equal to
In this case, it is known that -4 is less than 5, or:
-4 < 5.
~
Answer:
>
Step-by-step explanation:
because 5 is bigger than -4
What is the length of BC in the right triangle below?
B
00
A
15
с
A. 17
B. 60
C. 17
D. 289
Using Pythagorean Theorem
[tex]\\ \sf\longmapsto H^2=P^2+B^2[/tex]
[tex]\\ \sf\longmapsto H^2=8^2+15^2[/tex]
[tex]\\ \sf\longmapsto H^2=64+225[/tex]
[tex]\\ \sf\longmapsto H^2=289[/tex]
[tex]\\ \sf\longmapsto H=\sqrt{289}[/tex]
[tex]\\ \sf\longmapsto H=17[/tex]
BC=17Polygon mnopq is dialated by scale factor of 0.8 with the origin as the center dilation resulting in the image MNOPQ the coordinates of point M are (2,4) and the coordinates of point N are (3,5). The slope of MN is?
9514 1404 393
Answer:
1
Step-by-step explanation:
The slope is given by the formula ...
slope = (y2 -y1)/(x2 -x1)
slope = (5 -4)/(3 -2) = 1/1 = 1
The slope of MN is 1.
__
Dilation does not change the slope.
Assume x and y are two odd numbers and x/y is an integer.
Which of the following statements are true?
I. x + y is odd
2. xy is odd.
3. x/y is odd
4. x-y is odd
Answer:
Let us check these out one at a time:
1. x + y is odd. FALSE. The sum of 2 odd numbers is even.
2. xy is odd. TRUE. The product of 2 odd numbers is odd.
3. x/y is odd. TRUE. The ratio of 2 odd numbers is odd, if the ratio is an integer.
4. x - y is odd. FALSE. The difference of 2 odd numbers is even.
Only statements 2 and 3 are TRUE, so that makes (C) the correct answer.
Given that the supply and demand function for the product type is Qd = [tex]\sqrt{260-p}[/tex],
Qs = [tex]\sqrt{p-14}[/tex]. consumer surplus ??.
7. Ten samples of 15 parts each were taken from an ongoing process to establish a p-chart for control. a. Develop a p-Chart for 95 percent confidence (1.96 standard deviation). b. Based on the plotted data points, what comments can you make
Answer: Hello the table related to your question is attached below
answer:
a) attached below
b) The process is out of control because two ( 2 ) values from the defect rate table are out of the control limits at 95% as seen in the p-chart in question ( A )
Step-by-step explanation:
a) p-chart for 95% confidence
std = 1.96
Total defects = ∑ number of defective items in the sample = 10
number of samples = 10
sample size ( n ) = 15
The P value for the process is calculated as :
Total defects / ( number of sample * sample size )
= 10 / ( 15 * 10 ) = 10 / 150 = 0.067
standard deviation ( σ ) = [tex]\sqrt{\frac{p(1-p)}{n } } = \sqrt{\frac{0.067(1-0.067)}{15} }[/tex] = 0.065
next we determine the limits ( i.e. upper and lower )
UCL = p + zSp = 0.067 + 1.96(0.065 ) = 0.194
LCL = p - zSp = 0.067 - 1.96(0.065) = -0.060 ≈ 0 ( because LCL ≠ negative)
attached below is the required p-chart
b) The process is out of control because two ( 2 ) values from the defect rate table are out of the control limits at 95% as seen in the p-chart in question ( A )
WILL GIVE BRAINLIEST
Complete the equation describing how
x and y are related.
х
-3
-2
-1
0
1
2
3
y
12
8
4
0
-4
-8
-12
y = [? ]x
Answer:
[tex]y=4x[/tex]
Answer:
y = -4x
hope that helped.........
