Answer:
a) Hence the probability that the average test score in the class of size 25 exceeds 80.
P ( X > 74) = 0.9838
P ( Z > 2.14) = 0.0162
b) Hence the probability that the average test score for the class of size 64
P ( X > 74) = 0.9838
P ( Z > 2.14) = 0.0003
c) Probability of the difference exceeding 2.2 = 0.9936
P (Z < 2.49) = 0.0064
Step-by-step explanation:
Let's assume a normal distribution.
Now,
a) For a class of 25
[tex]P ( X > 74) = P (Z > 80 - 74/ 14\sqrt(25) )\\\\= P (Z < 6 / 2.8)\\\\= P ( Z < 2.14)\\= 0.9838\\[/tex]
[tex]P ( Z > 2.14) = 1- 0.9838\\= 0.0162[/tex]
b)
Similarly:
For the class of 64
[tex]P ( X > 74) = P (Z > 80 - 74/ 14\sqrt(64) )\\\\= P (Z < 6 / 1.75)= P ( Z < 3.428)\\= 0.9838\\[/tex]
[tex]P ( Z > 2.14) = 1- 0.9997\\= 0.0003[/tex]
c) Probability of the difference exceeding 2.2
[tex]= P (Z > 2.2/\sqrt{14 * {(1/25) + (1/64}\\[/tex]
[tex]= P (Z > 2.49)\\= 0.9936[/tex]
P (Z < 2.49)
= 1 - 0.9936
= 0.0064
if a circumference of a circle is 22cm.find it diameter take pie 22/7.
Answer:
➕
Step-by-step explanation:
i know the answer ok it is easy
A bicyclist is at point A on a paved road and must ride to point C on another paved road. The two roads meet at
an angle of 38° at point B. The distance from A to B is 18 mi, and the distance from B to C is 12 mi (see
the figure). If the bicyclist can ride 22 mph on the paved roads and 6.8 mph off-road, would it be faster for the bicyclist to ride from A to C on the paved roads or to ride a direct line from A to C off-road? Explain.
Answer:
Step-by-step explanation:
The diagrammatic expression to understand this question very well is attached in the image below.
By applying the law of cosine rule; we have:
a² = b² + c² - 2bc Cos A --- (1)b² = a² + c² - 2ac Cos B --- (2)c² = a² + b² - 2ab Cos C --- (3)From the diagram attached below, we need to determine the side "b" by using equation (2) from above:
b² = a² + c² - 2ac Cos B
From the information given:
a = 12 miles; c = 18 miles; ∠B = 38°
∴
replacing the values into the above equation:
b² = 12² + 18² - 2(12)(18) Cos (38°)
b² = 144 + 324 - 432 × (0.7880)
b² = 468 - 340.416
b² = 127.584
[tex]b = \sqrt{127.584}[/tex]
b = 11.30 miles
However, we are also being told that the speed from A → C = 6.8 mph
Thus, the time required to go from A → C can be determined by using the relation:
[tex]\mathbf{speed = \dfrac{distance}{time}}[/tex]
making time the subject of the formula, we have:
[tex]\mathbf{time= \dfrac{distance}{speed }}[/tex]
[tex]\mathbf{time= \dfrac{11.30}{6.8}}[/tex]
time = 1.66 hours
By using the paved roads, the speed is given as = 22 mph
thus, the total distance covered = |AB| + |BC|
= (18+12) miles
= 30 miles
∴
[tex]\mathbf{time= \dfrac{distance}{speed }}[/tex]
[tex]\mathbf{time= \dfrac{30}{22}}[/tex]
time = 1.36 hours
Therefore, the time used off-road = 1.661 hours while the time used on the paved road is 1.36 hours.
Since we are considering the shortest time possible;
We can conclude that it would be faster for the bicyclist to ride from A to C on the paved roads since it takes a shorter time to reach its destination compared to the time used off-road.
Learn more about Law of cosine here:
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It would be faster for the bicyclist to ride from A to C on the paved roads since the time to go from A to C on the paved roads is 1.4 h and the time to go from A to C off-road is 1.7 h.
To calculate which way would be faster we need to find the distance from point A to C with the law of cosines:
[tex] \overline{AC}^{2} = \overline{AB}^{2} + \overline{BC}^{2} - 2\overline{AB}\overline{BC}cos(38) [/tex]
Where:
[tex]\overline{AB}[/tex]: is the distance between the point A and B = 18 mi
[tex]\overline{BC}[/tex]: is the distance between the point B and C = 12 mi
[tex] \overline{AC} = \sqrt{(18 mi)^{2} + (12 mi)^{2} - 2*18 mi*12 mi*cos(38)} = 11.3 mi [/tex]
Now, let's find the time for the two following cases.
1. From point A to C on the paved roads (t₁)
[tex] t_{1} = t_{AB} + t_{BC} [/tex]
The time can be calculated with the following equation:
[tex] t = \frac{d}{v} [/tex] (1)
Where:
d: is the distance
v: is the velocity
Then, the total time that it takes the bicyclist to go from point A to C on the paved roads is:
[tex] t_{1} = t_{AB} + t_{BC} = \frac{18 mi}{22 mph} + \frac{12 mi}{22 mph} = 1.4 h = 84 min [/tex]
2. From point A to C off-road (t₂)
With equation (1) we can calculate the time to go from point A to C off-road:
[tex] t_{2} = \frac{\overline{AC}}{v_{2}} = \frac{11.3 mi}{6.8 mph} = 1.7 h = 102 min [/tex]
Therefore, it would be faster for the bicyclist to ride from A to C on the paved roads.
To find more about the law of cosines, go here: https://brainly.com/question/15740431?referrer=searchResults
I hope it helps you!
Factor this polynomial expression.
3x^2 - 12x+ 12
A. (3x - 2)(x-6)
B. 3(x-2)(x + 2)
C. 3(x-2)(x-2)
D. 3(x + 2)(x + 2)
Salaries of entry-level computer engineers have Normal distribution with unknown mean and variance. Three randomly selected computer engineers have following salaries (in $1000s): 70, 80, 90. The average and the standard deviation of the data in the sample are 80 and 10. Using hypothesis testing, determine if this sample provides a sufficient evidence, at a 10% level of significance, that the average salary of all entry-level computer engineers is different from $60,000.
a. Null hypothesis.
b. alternative hypothesis.
c. test statistic.
d. acceptance region.
Answer:
H0 : μ = 60000
H1 : μ ≠ 60000
Test statistic = 3.464
Step-by-step explanation:
Given :
Sample mean salary, xbar = 80000
Sample standard deviation, s = 10000
Population mean salary , μ = 60000
Sample size, n = 3
Hypothesis :
H0 : μ = 60000
H1 : μ ≠ 60000
The test statistic :
T = (xbar - μ) ÷ (s/√(n))
T = (80000 - 60000) ÷ (10000/√(3))
T = 20000 / 5773.5026
T = 3.464
The Decison region :
If Tstatistic >Tcritical
Tcritical at 10%, df = 2 ; two - tailed = 2.9199
Tstatistic > Tcritical ; He
Primo car rental agency charges $21 per day plus $0.20 por milo. Ultimo car rental agency charges $24 per day plus $1.00 per milo. Find the daily mileage for which the Ultimo charge is four times the Primo charge.
The mileage is
Answer:
300 miles
Step-by-step explanation:
Let us consider the miles they travelled is 'm'
Mileage for Primo= 21 + (m × 0.20) = 21+0.2m
Mileage for Ultimo= 24+ ( m× 1.00) = 24 + m
Question says The mileage is equal when Ultimo's charge is 4× Primo
Thus,
4 × (21+0.2m) = 24+ m
84 + 0.8m = 24 + m
60 = 0.2m
m = 300
½ sejam berapa minit?
Answer:
1/2 jam 30 menit mungkin?
1/2 jam adalah 30 minit
1/2 × 60 = 30 mins
English translation
1/2 an hour is 30 minutes
1/2 × 60 = 30 mins
Answered by Gauthmath must click thanks and mark brainliest
In a 2-digit number, the tens digit is 5 less than the units digit. If you reverse the number, the result is 7 greater than double the original number. Find the original number.
The original number is 38
A 2-digit number can be written as:
N = a*10 + b*1
Where a is the tens digit, and b is the units digit, these two are single-digit numbers.
We know that:
"the tens digit is 5 less than the units digit."
This means that:
a = b - 5
(notice that a must be larger than zero and smaller than 10, from this, we can conclude that b is a number in the range {6, 7, 8, 9})
"If you reverse the number, the result is 7 greater than double the original number"
The reverse number is:
b*10 + a
and this is 7 greater than 2 times the original number, then:
b*10 + a = 7 + 2*(a*10 + b)
Then we found two equations:
a = b - 5
b*10 + a = 7 + 2*(a*10 + b)
Replacing the first equation in the second, we get:
b*10 + (b - 5) = 7 + 2*((b - 5)*10 + b)
Now let's solve that:
b*10 + b - 5 = 7 + 2*(11*b - 50)
11*b - 5 = 7 + 22*b - 100
-5 - 7 + 100 = 22*b - 11*b
88 = 11*b
88/11 = b = 8
Now that we know that b = 8, we can use the equation:
a= b - 5
a = 8 -5 = 3
Then the original number is:
a*10 + b = 3*10 + 8 = 38
The original number is 38
If you want to read more about this, you can see:
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look at the image below
Answer:
201.1 km²
Step-by-step explanation:
Surface area of the figure,
4πr²
= 4×π×4²
= 64π
= 201.1 km² (rounded to the nearest tenth)
by selling a purse for rupees 250 Rajan loses one sixth of what cost should find the cost price of the first her loss percentage
Answer:
300, 16.67%
Step-by-step explanation:
Let x be the cost price. x-(1/6)x=250. 5x/6=250. x=300. Losss percentage is 16.67%
Solve 5 (2x + 1 ) + 4 = 6 ( 3x + 2) - 7
5(2x+1)+4=6(3x+2)-7
10x+5+4=18x+12-7
10x-18x=12-7-5-4
-8x=-4 (-1)
8x=4
x=4/8 (/4)
x=1/2
Answer:
x = 1/2
Step-by-step explanation:
5(2x + 1) + 4 = 6 (3x + 2) - 7
~Simplify both sides
10x + 9 = 18x + 5
~Subtract 9 from both sides
10x = 18x - 4
~Subtract 18x to both sides
-8x = -4
~Divide -8 to both sides
x = 1/2
Best of Luck!
5.
A number is squared, then multiplied by 6. The result is 54. What was the number?
Answer:
Answer:
± 3
Step-by-step explanation:
let n be the number then the number squared is n² , so
6n² = 54 ( divide both sides by 6 )
n² = 9 ( take the square root of both sides )
n = ± [tex]\sqrt{9}[/tex] = ± 3
That is the number is 3 or - 3
You have $90 in your bank account. Each work you plan to deposit $3 from your allowance and $25 from your paycheck. The equation b: 90+ (25+5)w gives the amount b in your account after w woeks. How rary works from
now will you have $220 in your bank account?
There will be 5220 in the account after works
(Type a whole number
Given coordinates A(3,3),B(2,5),C(4,3) complete transformation. Complete double reflection over the lines y=2 followed by y=0.
9514 1404 393
Answer:
A"(3, -1)B"(2, 1)C"(4, -1)Step-by-step explanation:
Reflection over 'a' then over 'b' will result in a translation of 2(b -a). Here, we have a=2, b=0, so the translation is 2(0-2) = -4. The reflection is over horizontal lines, so the transformation is ...
(x, y) ⇒ (x, y -4)
A(3, 3) ⇒ A"(3, -1)
B(2, 5) ⇒ B"(2, 1)
C(4,3) ⇒ C"(4, -1)
A farmer wishes to construct a fence around his rectangular field. The farmer has 150 feet of fence and
wishes to have the length be three more than the width. What is the width of the field. Make sure and
include feet in your answer.
Help
Answer:
The width is 36 feet
Step-by-step explanation:
If the width of the fence is x then its length is x+3.
The perimeter is 150 feet, so we have the equation:
2(x + x + 3) = 150
4x + 6 = 150
x = 144/4 = 36 feet
 evaluate P(6,2) or 6p2
Answer:
30
Step-by-step explanation:
Permutation equation: [tex]\frac{n!}{(n-r)!}[/tex]
n = Total number of objects, r = Number of objects selected
[tex]_6P_2=\frac{6!}{(6-2)!}=30[/tex]
HELPPPP PLZ
Witch statement is true about the value of |6|?
Answer:
The third choice is the correct one.
Step-by-step explanation:
The absolute value of six means that it's the distance from 0 to six, and that distance will be positive regardless of the number being negative or not.
Answer: The third answer is correct
Step-by-step explanation:
Since |6| is the absolute value of positive six, the value of an absolute value of any number is always positive.
Can someone please help me solve the equation?
Subtracting 10 from the original equation will shift the graph down 10 units
The answer is D.
Use a calculator to find
the mean of the data.
{217, 253, 214, 247,
217, 253, 232, 246,
223, 227, 229, 247,
206, 241, 239, 223,
222, 216, 252, 209,
236, 256}
A. 230.811
B. 231.045
C. 232.045
D. 232.811
Answer:
232.045
Step-by-step explanation:
217 + 253 + 214 + 247 + 217 + 253 + 232 + 246 + 223 + 227 + 229 + 247 + 206 + 241 + 239 + 223 + 222 + 216 + 252 + 209 + 236 + 256 = 5105
5105 / 22 = 232.045454545
write an absolute value equations to satsify the given solution set shown on a number line -1/2 1/2 and a
Plz help fast
9514 1404 393
Answer:
|x| = 1/2
Step-by-step explanation:
Perhaps the simplest equation is ...
|x| = 1/2
__
You could get more elaborate:
|2x| = 1
3 -|6x| = 0
vector v has a horizontal vector component with magnitude 19 and a vertical vector component with magnitude 35. what is the acute angle theta formed by v and positive x-axis?
9514 1404 393
Answer:
61.5°
Step-by-step explanation:
The tangent relation is useful here. The angle is opposite the vertical side and adjacent to the horizontal side of the right triangle.
Tan = Opposite/Adjacent
tan(α) = 35/19
α = arctan(35/19) ≈ 61.5°
The angle made by v and the positive x-axis is 61.5°.
In an experiment, the initial temperature of a solution is -5 °C. The solution is heated up at 3 °C per minute for 19 minutes and then it is cooled at 4 °C per minute for 6 minutes. Calculate the final temperature, in °C, of the solution.
Answer:
28°C
Step-by-step explanation:
First you do 3*19=57°C
-5+57= 52°C
then you do 4*6=24 °C
as its being cooled you takeaway
52-24=28°C
Karen is having a party. She'll have 4 tables for every 12 guests. Complete the table below showing the number of tables and the number of guests.
Jua Kali Products Ltd has been in operation for the last 10 years. Its annual revenue and cost functions take form of quadratic functions. The following data was obtained from the records of the company. Year 2017 2018 2019 Units produced and sold (000) 5 10 15 Revenue (sh000) 1900 3600 5100 Cost (sh000) 7525 7100 6725 Required: The revenue and cost functions (10 marks) The breakeven number of units (5 marks)
Answer:
Step-by-step explanation:
vxcvxcvxcvxcvxcvcxvxcbcvbcvnxcgjfgjfgjghjghjghjghj
The revenue function is y₁ = –4x² + 400x, the cost function is y₁ = x² – 100x + 8000, and the break-even number of units is 20 or 80.
What is a quadratic equation?It is a polynomial that is equal to zero. Polynomial of variable power 2, 1, and 0 terms are there. Any equation having one term in which the power of the variable is a maximum of 2 then it is called a quadratic equation.
Jua Kali Products Ltd has been in operation for the last 10 years.
Its annual revenue and cost functions take the form of quadratic functions.
The following data was obtained from the records of the company.
Year Unit Sold Revenue Cost
2017 5 1900 7525
2018 10 3600 7100
2019 15 5100 6725
We know that the quadratic equation is given as
[tex]\rm y = ax^2 + bx + c[/tex]
Let y₁ be the revenue function, y₂ be the cost function and x be the unis sold.
Then the revenue function will be
1900 = 25a + 5b + c ...i
3600 = 100a + 10b + c ...ii
5100 = 225a + 15b + c ...iii
From equations (i), (ii), and (iii), we have
a = –4, b = 400, and c = 0
Then the revenue function will be
y₁ = –4x² + 400x
Similarly, the cost function will be
7525 = 25a + 5b + c ...1
7100 = 100a + 10b + c ...2
6725 = 225a + 15b + c ...3
From equations 1, 2, and 3, we have
a = 1, b = –100, and c = 8000
Then the cost function will be
y₁ = x² – 100x + 8000
For the break-even units, the cost function and the revenue function will be equal. Then we have
[tex]\begin{aligned} x^2 -100x + 8000 &= -4x^2 + 400x\\\\5x^2 -500x + 8000 &= 0\\\\x^2 - 100x + 1600 &= 0\\\\x^2 - 80 x - 20x + 1600 &= 0\\\\x(x-80) - 20 (x-80) &= 0\\\\(x-80)(x-20) &= 0\\\\x &= 20, 80 \end{aligned}[/tex]
More about the quadratic equation link is given below.
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Could you guys answer this for me by 12am!
Answer:
-3
Step-by-step explanation:
Slope is y2 - y1 / x1 - x2.
So, let's take two random points; I have chosen (0, 3) and (2, -3).
Excellent. Let's calculate the slope.
Slope = (-3 - 3) / (2 - 0) = -6 / 2 = -3.
Hope this helps!
2 hundreds equal how many tens?
Lets see if ya'll know the answer cause i do
Answer:
200 is equal to 20 tens I guess lol
Answer:
20 tens
Step-by-step explanation:
200÷10=20 groups of ten
the area of a rectangular park is 7/8 sqaure mile. the length of the park is 3/4 mile. what is the width of the park?
Answer:
7/6
Step-by-step explanation:
since the formula of area is length times width,you have to divide the area by the length to find the width
area=length×width
the width will be
width=area÷length
=7/8÷3/4
7/8×4/3
7/2×1/3
7/6
that's the width you can prove it by multiplying the length times the width to see if you will get 7/8..
I hope this helps
For 32 = 5X + 2, what is the first step in solving for X?
Answer:
-2 from both sides
Step-by-step explanation:
32=5x+2
-2 -2
________
30=5x
__=__
5 5
6=x
The first step to solve for X is to use subtraction property of equality to subtract 2 from both sides.
How to solve algebraic equations?
We are given the algebraic equation;
32 = 5X + 2
The first step to solve for X is to use subtraction property of equality to subtract 2 from both sides to get;
32 - 2 = 5X + 2 - 2
30 = 5X
Divide both sides by 5 using division property of equality to get;
X = 6
Read more about Algebraic Equations at; https://brainly.com/question/16863577
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How do I graph x+3y≥12?
Select the correct answer from each drop-down menu. Complete the statement. The solutions of sin2x= √3/2
are : 30 / 120 / 150 / 330
and
45 / 60 / 105 / 135
What are the correct solutions?
Answer:
henc X = 30°
Step-by-step explanation:
here is the proof
when X=30° then
sin2x = sin2×30
=sin 60°
= √3/2
or else,
putting value of X = 30° then
sin2x= 2sinxcosx
= 2×sin30°×cos30°
=2×1/2×√3/2
= 2√3/4
= √3/2
hence proved sin2x= √3/2.
A newsletter publisher believes that less than 61% of their readers own a laptop. Is there sufficient evidence at the 0.02 level to substantiate the publisher's claim? State the null and alternative hypotheses for the above scenario.
Answer: See explanation
Step-by-step explanation:
From the information given in the question, we are informed that a newsletter publisher believes that less than 61% of their readers own a laptop.
The null hypothesis will be: H0: p ≥ 0.61
The alternative hypothesis will be: Ha: p < 0.61.
