Answer:
W = 650000 ftlb
Step-by-step explanation:
Parameters given:
Weight of the cable = 2 lb/ft
Weight of the coal = 800 lb
Depth of the shaft, x = 500 ft
The total work done in this system is given by the sum of the work done on the coal and the work done on the shaft.
WORK DONE ON THE COAL
The work done on the coal is given as:
[tex]W_{coal}[/tex] = Weight of coal * distance
[tex]W_{coal}[/tex] = 800 * 500
[tex]W_{coal}[/tex] = 400000 ftlb
WORK DONE ON THE SHAFT
If we partition the cable into several segments of depth Δx, we can find the work done on the cable.
The work done on the shaft is given as:
[tex]W_{shaft}[/tex] = 2Δx * x
[tex]W_{shaft}[/tex] = 2xΔx
=> [tex]W_{shaft}[/tex] = [tex]\int\limits^{500}_{0} {2x} \, dx[/tex]
[tex]W_{shaft}[/tex] = [tex]\frac{2x^{2}}{2} \left \{ {{500} \atop {0}} \right.[/tex]
[tex]W_{shaft}[/tex] = [tex]500^{2} - 0^{2}[/tex]
[tex]W_{shaft}[/tex] = 250000 ftlb
Therefore, total work done is:
[tex]W_{total} = 250000 + 400000[/tex]
[tex]W_{total} = 650000 ftlb[/tex]
The work done to lift the coal up the mine shaft is 900,000 ft-lbf.
To find the work done, we can use the formula:
Work = Force x Distance
First, we need to calculate the force. The cable weighs 2 lbf/ft, so the total weight of the cable is 2 lbf/ft x 500 ft = 1000 lbf. The force to lift the coal is 800 lbf. Therefore, the total force is 1000 lbf + 800 lbf = 1800 lbf.
Next, we can calculate the work done by multiplying the force by the distance: Work = 1800 lbf x 500 ft = 900,000 ft-lbf.
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Why is the answer A?
Step-by-step explanation:
F(x) is the antiderivative (or integral) of f(x).
F(x) = ∫ f(x) dx
F(x) = sin(1/(x² + 1))
∫₁² f(x) dx
= F(2) − F(1)
= sin(1/(2² + 1)) − sin(1/(1² + 1))
= sin(⅕) − sin(½)
= -0.281
Scientific notation is ________.a. used to keep track of very small and very large numbers during mathematical calculations b. used to accurately measure volumes used to measure length with precision c. used to communicate the level of precision
Answer:
A. Used to keep track of very large and very small numbers during mathematical calculations.
Step-by-step explanation:
Some very large and small numbers are not easily represented in mathematical calculations. Using scientific notations help us to represent very large and small numbers to the power of 10.
Are these ratios equivalent?
18 professors : 5 students
36 professors : 10 students
yes/no
Answer:
yes
Step-by-step explanation:
Answer:
Yes
Step-by-step explanation:
18 : 5
36 : 10
36/2 : 10/2
18 : 5
Jason drew a scale drawing of a city. He used the scale 1 inch : 4 yards. A neighborhood park is 68 yards wide in real life. How wide is the park in the drawing?
Answer:
17 inches
Step-by-step explanation:
The scale is the same at every distance, so ...
[tex]\dfrac{\text{1 in}}{\text{4 yd}}=\dfrac{w}{\text{68 yd}}\\\\\text{(1 in)}\dfrac{\text{68 yd}}{\text{4 yd}}=w \qquad\text{multiply by 68 yd}\\\\\text{17 in}=w[/tex]
The park is 17 inches wide on the drawing.
Answer:
17 in
Step-by-step explanation:
68 yds divided by 4 equals 17 in
x4+x3+7x2-6x+8 / x2+2x+8
Answer:
The Final answer will be [tex]x^2-x+1[/tex] with remainder 0.
Step-by-step explanation:
We have attached the division for your reference.
Given:
Dividend = [tex]x^4+x^3+7x^2-6x+8[/tex]
Divisor = [tex]x^2+2x+8[/tex]
Explaining the division we get;
Step 1: First when we divide the Dividend [tex]x^4+x^3+7x^2-6x+8[/tex] with divisor [tex]x^2+2x+8[/tex] we will first multiply [tex]x^2[/tex] with the divisor then we get the Quotient as [tex]x^2[/tex] and Remainder as [tex]-x^3-x^2-6x+8[/tex]
Step 2: Now the Dividend is [tex]-x^3-x^2-6x+8[/tex] and Divisor [tex]x^2+2x+8[/tex] is we will now multiply [tex]-x[/tex] with the divisor then we get the Quotient as [tex]x^2-x[/tex] and Remainder as [tex]x^2+2x+8[/tex]
Step 3: Now the Dividend is [tex]x^2+2x+8[/tex] and Divisor is [tex]x^2+2x+8[/tex] we will now multiply 1 with the divisor then we get the Quotient as [tex]x^2-x+1[/tex] and Remainder as 0.
Hence The Final answer will be [tex]x^2-x+1[/tex] with remainder 0.
Two trained professionals observe the behavior of children in a classroom. They each rate observed behaviors using the same form and the number of items that were rated the same is calculated. This is an example of which type of reliability?
a. inter-rater reliability
b. test-retest reliability
c. none of the above
d. parallel reliability
Answer: a) inter rater
Step-by-step explanation:
Inter rater is a type of relativity that measures the degree of agreement between rates and judges.
It is used to ensure that the score gotten among rates are in consensus with one another.
Inter rater relativity reduces inconsistency in the application of data collected.
The scenario where two trained professionals rate observed children's behaviors using the same form and comparing their ratings exemplifies inter-rater reliability (option a), focusing on the consistency of measurements between different observers.
The type of reliability being described in the scenario is inter-rater reliability. This type of reliability is concerned with the level of agreement between two or more independent observers or raters when they assess the same behaviors using a standardized method or form. To ensure that a study's measures are consistently capturing the concepts of interest, researchers often assess inter-rater reliability.
Inter-rater reliability can involve qualitative categories (like behavioral observations in a classroom) where the agreement percentage reflects the reliability. Alternatively, for measurements on interval or ratio scales, the correlation between the raters' scores can be used. When two professionals observe children and rate their behavior on the same form, looking for agreement in items rated, they establish inter-rater reliability.
What is the rate of increase for the function f(x) = One-third (RootIndex 3 StartRoot 24 EndRoot) Superscript 2 x? One-third 2RootIndex 3 StartRoot 3 EndRoot 4 4RootIndex 3 StartRoot 9 EndRoot
Answer:
D, [tex]4^{3} \sqrt{9}[/tex]
Answer:
d
Step-by-step explanation:
Find the least-squares regression line: ŷ =b0+b1x, through the points (−1,0),(0,9), (4,13), (8,20), (10,23). For x=5, what is ŷ? For x=9, what is ŷ?
The value of y =14.45689 when x=5 and y= 21.74137 when x= 9.
What is Regression line?An estimate of the line that depicts the actual, but unidentified, linear relationship between the two variables is called a regression line. When the value of the explanatory variable is known, the regression line's equation is used to predict (or estimate) the value of the response variable.
Because it is the line that fits the points the best when drawn through them, the regression line is occasionally referred to as the "line of best fit." It is a line that minimises the difference between the projected and actual scores.
Given Data:
(−1,0),(0,9), (4,13), (8,20), (10,23).
Sum of X = 21
Sum of Y = 65
Mean X = 4.2
Mean Y = 13
Sum of squares (S[tex]S_x[/tex]) = 92.8
Sum of products (SP) = 169
Regression Equation = ŷ = bx + a
b = SP/S[tex]S_x[/tex] = 169/92.8 = 1.82112
a = [tex]M_y[/tex]- [tex]bM_x[/tex]= 13 - (1.82x4.2) = 5.35129
ŷ = 1.82112x + 5.35129
For x= 5
ŷ = 1.82112(5) + 5.35129
ŷ = 14.45689
and, when x= 9
ŷ = 1.82112(9) + 5.35129
ŷ = 21.74137
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Final answer:
The least-squares regression line equation is ŷ = -1.72 + 2.18x. For x = 5, ŷ is approximately 9.88. For x = 9, ŷ is approximately 18.62.
Explanation:
To find the least-squares regression line, we need to use the formula ŷ = b0 + b1x, where b0 is the y-intercept and b1 is the slope. Using the coordinates of the given points, we can calculate the values of b0 and b1. Substituting these values into the formula, we get ŷ = -1.72 + 2.18x. For x = 5, we can plug this value into the equation: ŷ = -1.72 + 2.18(5) = 9.88. Similarly, for x = 9, we can substitute x into the equation: ŷ = -1.72 + 2.18(9) = 18.62.
What is the momentum of each hockey player? Hockey player 1 has a mass of 65 kg and a velocity of 3.8 m/s
Hockey player 2 has a mass of 58 kg and a velocity of 4.3 m/s
Answer:
Momentum of hocking player [tex]1:[/tex] [tex]247\ kg\ m/s[/tex]
Hockey player [tex]2:[/tex] [tex]=249.4\ kg\ m/s[/tex]
Step-by-step explanation:
For first hockey player :
Given that
mass (m) [tex]=65\ kg[/tex]
Velocity (v) [tex]=3.8\ m/s[/tex]
[tex]p=mv\................(1)[/tex]
where [tex]p[/tex] is momentum
put the value in equation (1)
[tex]p=65\times3.8\\\\p=247kg\times m/s[/tex]
For second hockey player :
Given that
mass (m) [tex]=58\ kg[/tex]
velocity (v) [tex]=4.3\ m/s[/tex]
[tex]p=mv\ ...............(2)[/tex]
Where [tex]p[/tex] is momentum
put the value in equation (2)
[tex]p=58\times4.3\\p=249.4\ kg\times m/s[/tex]
Please help i need answer
Answer:
Step-by-step explanation:
Triangle ABC is a right angle triangle.
From the given right angle triangle,
BC represents the hypotenuse of the right angle triangle.
With m∠C as the reference angle,
AC represents the adjacent side of the right angle triangle.
AB represents the opposite side of the right angle triangle. if Sin C = 15/17, it means that
Opposite side = 15
Hypotenuse = 17
We would find the adjacent side by applying Pythagorean theorem. Therefore,
Adjacent side² = 17² - 15² = 64
Adjacent side √ 64 = 8
To determine the ratio of Cos C, we would apply
the cosine trigonometric ratio.
Cos θ = adjacent side/hypotenuse. Therefore,
Cos C = 8/17
You have just used the network planning model and found the critical path length is 30 days and the variance of the critical path is 25 days. The probability that the project will be completed in 33 days or less is equal to:_______.
Answer:
0.726 is the probability that the project will be completed in 33 days or less.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 30 days
Variance = 25 days
Standard Deviation,
[tex]\sigma = \sqrt{\text{Variance}} = \sqrt{25} = 5[/tex]
We assume that the distribution of path length is a bell shaped distribution that is a normal distribution.
Formula:
[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]
P(completed in 33 days or less)
[tex]P( x \leq 33) = P( z \leq \displaystyle\frac{33 - 30}{5}) = P(z \leq 0.6)[/tex]
Calculation the value from standard normal z table, we have,
[tex]P(x \leq 33) = 0.726 = 72.6\%[/tex]
0.726 is the probability that the project will be completed in 33 days or less.
Mary buys p peaches at the farmer's market for d dollars each. She spends a total of tdollars on peaches. Create an equation that represents the relationship between t and p.
An equation that represents the relationship between t and p is [tex]\rm Cost \ of \ each \ peaches = \dfrac{p \times d }{t}[/tex].
Given
Mary buys p peaches at the farmer's market for d dollars each.
She spends a total of t dollars on peaches.
The cost of each peach is;
[tex]\rm Cost \ of \ each \ peaches = \Total \ number \ of \ peaches \times Amount \ of \ each \ peaches\\\\Cost \ of \ each \ peaches= p \times d[/tex]
Therefore;
An equation that represents the relationship between t and p is;
[tex]\rm Cost \ of \ each \ peaches = \dfrac{Total \ number \ of \ peaches \times Amount \ of \ each \ peaches} {Total \ money\ spend \ on \ peaches}\\\\Cost \ of \ each \ peaches = \dfrac{p \times d }{t}[/tex]
Hence, An equation that represents the relationship between t and p is [tex]\rm Cost \ of \ each \ peaches = \dfrac{p \times d }{t}[/tex].
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If Felicia lives 1 1/5 miles from the school and 9/10mile from the doctor field how much closer would she live if she lived 7/10 like from the doctor field
In how many ways can 3 apple trees, 4 peach trees, and 2 plum trees be arranged along a fence line if one does not distinguish between trees of the same kind?\
Answer:
24 ways
Step-by-step explanation:
4x3x2
12x2
24
Omar begins training for a 5 km race by running 0.75 km the first day, 0.85 km the second day, and 0.95 km the third day. If he keeps increasing his distance each day according to the pace of his first three days, what is the first day in his training program that Omar will run greater than 5 km?
Final answer:
Omar will run greater than 5 km on the 44th day of his training program, as this is when the distance he runs each day according to the pattern in his training exceeds 5 km.
Explanation:
Omar increases his running distance each day by 0.10 km (from 0.75 km on the first day to 0.85 km on the second, then to 0.95 km on the third, and so on). To find the first day he will run greater than 5 km, we can create a sequence to represent the distances he runs each day. Since the difference between consecutive days is constant (0.10 km), this is an arithmetic sequence.
The first term (a1) of the sequence is 0.75 km, and the common difference (d) is 0.10 km. The nth term of an arithmetic sequence is given by an = a1 + (n - 1)d. We need to find the smallest n such that an > 5 km.
Setting up the inequality, we get:
0.75 + (n - 1)0.10 > 5
(n - 1)0.10 > 5 - 0.75
(n - 1)0.10 > 4.25
n - 1 > 42.5
n > 43.5
Since n must be a whole number, Omar will run greater than 5 km on day 44 of his training program.
The conference method estimates cost functions: A. Using quantitative methods that can be very time consuming and costly B. Based on analysis and opinions gathered from various departments C. Using time-and-motion studies D. By analyzing the relationship between inputs and outputs in physical terms
Answer:
B. Based on analysis and opinions gathered from various departments
Step-by-step explanation:
Conference method of cost estimation envisages a widespread process in which head of different unit of organisation is consulted and their skill in their area of operation is tapped to make estimation of cost of the operation of different department.
If 64.7% 2017 college students attended a 4year program and u took a random 500students in 2017 how many college students would you expect to attend 4year program
Answer:
Around 337 students
Step-by-step explanation:
We are given the following in the question:
Percentage of student who attended a 4 year programme in 2017 = 64.7%
Sample size, n = 500
We have to find he expected number of students who would attend 4 year programme.
Formula:
[tex]67.4\% \times n\\=67.4\% \times 500\\\\=\dfrac{67.4}{100}\times 500\\\\=337[/tex]
Thus, around 337 students are expected to attend 4 year program.
Please help, will mark brainliest if correct!!!
Answer:8.5
Step-by-step explanation:
Pythagorean Theorem
A
a^2 + b^2 = c^2
3^2 + 8^2 = c^2
9 + 64 = c^2
73 = c^2
C= Sqrt (73)
C = 8.5
Claudia scores 275 points on a video game. Hannah scores 268 points on the same video game. The high score for the same game is 306. How many points did the girls score in all?
Answer:
543
Step-by-step explanation:
Given: Claudia score= 275 points
Hannah score= 268 points
Now, finding the how many points girls scored in the game.
Total score by girls= [tex]Score\ of\ Claudia + score\ of\ Hannah[/tex]
⇒ Total score by girls= [tex]275+268[/tex]
Total score by girls= 543.
Hence, Total score by girls is 543.
Humberto evaluates the expression 4t2 for t=3. He correctly substitutes 3 for t in the expression, but then says that the value is 144. However, he is incorrect!
Answer:
36
Step-by-step explanation:
He multiplied the four and the three first when he multiplied the equation together. However, according to the order of the operations, he was supposed to square three first. 3^2 = 9. Then multiplied 9*4 = 36.
Which set of ordered pairs has point symmetry with respect to the origin (0, 0)?
(-8, 3), (8, -3)
(-8, 3), (-3, 8)
(-8, 3), (-8, -3)
(-8, 3), (8, 3)
Answer:
(-8, 3), (8, -3)
Step-by-step explanation:
Point symmetry about origin means reflection of the given point about the origin.
The reflection of a point about the origin will cause the 'x' and 'y' value of the point to change its sign.
Therefore, the coordinate rule for point symmetry about the origin is given as:
[tex](x,y)\to (-x,-y)[/tex]
Now, let us check each of the given options.
Option 1:
(-8, 3), (8, -3)
Now, if (x, y) = (-8, 3), then its point symmetry is given as (-(-8), -3) = (8, -3)
So, option 1 is correct.
Option 2:
(-8, 3), (-3, 8)
Now, if (x, y) = (-8, 3), then its point symmetry is given as (-(-8), -3) = (8, -3) ≠ (-3, 8)
So, option 2 is not correct.
Option 3:
(-8, 3), (-8, -3)
Now, if (x, y) = (-8, 3), then its point symmetry is given as (-(-8), -3) = (8, -3) ≠ (-8, -3)
So, option 3 is not correct.
Option 4:
(-8, 3), (8, 3)
Now, if (x, y) = (-8, 3), then its point symmetry is given as (-(-8), -3) = (8, -3) ≠ (8, 3)
So, option 4 is not correct.
Hence, only option 1 is correct.
Can someone please help me with this? will give you brainiest if correct
Thank you so much <3
Answer: The solution is [2, 1]
Step-by-step explanation:
The given system of simultaneous equations is expressed as
7x - 6y = - 20 - - - - - - - - - - 1
3x + 5y = - 1 - - - - - - - - - - - - -2
We would eliminate x by multiplying equation 1 by 3 and equation 2 by 7. It becomes
21x - 18y = - 60 - - - - - - - - - - 3
21x + 35y = - 7 - - - - - - - - - - 4
Subtracting equation 4 from equation 3, it becomes
- 53y = - 53
Dividing the left hand side and the right hand side of the equation by - 53, it becomes
- 53y/ - 53 = - 53/ - 53
y = 1
Substituting y = 1 into equation 2, it becomes
3x + 5 × 1 = - 1
3x + 5 = - 1
Subtracting 5 from the left hand side and the right hand side of the equation, it becomes
3x + 5 - 5 = - 1 - 5
3x = - 6
Dividing the left hand side and the right hand side of the equation by 3, it becomes
3x/3 = - 6/3
x = 2
A homes value increases at a average rate of 5.5% each yea. The current value is $120,000. What function can be used to find the value of the home after X years?
Answer: the function is
A = 120000(1.055)^x
Step-by-step explanation:
A homes value increases at an average rate of 5.5% each year. The growth rate is exponential. We would apply the formula for exponential growth which is expressed as
A = P(1 + r/n)^ nt
Where
A represents the value of the home after t years.
n represents the period of growth
t represents the number of years.
P represents the initial value of the home.
r represents rate of increase in value.
From the information given,
P = 120000
r = 5.5% = 5.5/100 = 0.055
n = 1
Therefore
A = 120000(1 + 0.055/1)^ x × 1
A = 120000(1.055)^x
Alice has seven times the amount of pens that Maurice has. Paul has two-thirds of the amount of pens as Alice and Suzy have combined. Dawn has a dozen more pens than Paul. Suzy has half the pens that Maurice has. If Suzy has 2 pens, how many does Dawn have?
Answer:
Dawn has 32 pens.
Step-by-step explanation:
Let No. of pens Alice has = ALet No. of pens Maurice has = M Let no of pens Paul has = P Let no. of pens Suzy has = S Let no of pens Dawn has = DGiven :
A = 7M P = 2/3 (A + S) D = P + 12 S = 1/2 MIf S = 2 {Given} M = 4 [∵ S = 1/2 M → M = 2S = 2X(2) ] A = 28 [ ∵ A = 7M → A = 7 x 4 ] P = 20 [∵ P = 2/3 (A+S) → P = 2/3 (28 + 2) = 2/3 (30) ] D = 32 [ ∵ D = P + 12 → D = 20 + 12 ]By following the relationships between the number of pens each person has, it is calculated that Dawn has 32 pens.
Explanation:This is a multi-step problem involving proportions and addition. First, we determine Maurice's number of pens based on Suzy's: because Suzy has half the pens Maurice does, and Suzy has 2 pens, Maurice therefore has 4 pens. Then, to find out how many pens Alice has, we multiply Maurice's number of pens by 7 (Alice having 7 times Maurice's number of pens), hence Alice has 28 pens. As Paul has two-thirds the number of all the pens that Alice and Suzy have (28 + 2 = 30 pens), Paul has 20 pens. Finally, as Dawn has a dozen more pens than Paul, Dawn has 32 pens (20 + 12).
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Lailah earns $9 per week working at the aquarium. Write and solve an inequality that can be used to find how many hours she must work in a week to earn at least $135.
Answer:
$9 per hour (not week)
9x > or = 135
x > or = 45 hours she must work
Step-by-step explanation:
Answer: she must work for at least 15 hours in a week to earn at least $135
Step-by-step explanation:
Let x represent the number of hours that Lailah must work in a week to earn at least $135.
Lailah earns $9 per week working at the aquarium. This means that in a week in which she worked for x hours, the total amount of money that she would earn is 9x
Therefore, the inequality that can be used to find how many hours she must work in a week to earn at least $135 would be
9x ≥ 135
x ≥ 135/9
x ≥ 15
ABCD is a rhombus. If AC = 8 cm and BC = 6 cm, what is the area of the rhombus?
Answer:24, it depend upon the picture
Step-by-step explanation:
if the ac and bc are diagonals the area of rhombus equal to 24.because area of the rhombuss = pq/2where p and q are the diagonals
The cost of 3 boxes of envelopes and 4 boxes of notebook paper is $22.65. Two boxes of envelopes and 6 boxes of notebook paper cost $24.60. Find the cost of each.
Answer: the cost of one box of envelope is $3.75.
the cost of one box of notebook paper is $2.85
Step-by-step explanation:
Let x represent the cost of one box of envelope.
Let y represent the cost of one box of notebook paper.
The cost of 3 boxes of envelopes and 4 boxes of notebook paper is $22.65. This means that
3x + 4y = 22.65 - - - - - - - - - - -1
Two boxes of envelopes and 6 boxes of notebook paper cost $24.60. This means that
2x + 6y = 24.6 - - - - - - - - - - -2
Multiplying equation 1 by 2 and equation 2 by 3, it becomes
6x + 8y = 45.3
6x + 18y = 73.8
Subtracting, it becomes
- 10y = - 28.5
y = - 28.5/-10
y = 2.85
Substituting y = 2.85 into equation 1, it becomes
3x + 4 × 2.85 = 22.65
3x + 11.4 = 22.65
3x = 22.65 - 11.4 = 11.25
x = 11.25/3 = 3.75
While visiting a pet store, you notice that there are only birds and cats in the cages. You can't help but wonder how many of each animal there is in the yard. But when you ask the store manager how many of each animal he has, he refuses to give you a direct answer. He says there are 16 animal heads and 42 animal feet. How many birds and cats are there in the pet store?
Answer: there are 11 birds and 5 cats
Step-by-step explanation:
Let x represent the number of birds in the pet store.
Let y represent the number of cats in the pet store.
A bird has one head and a cat also has one head. The store manager says that there are 16 animal heads in the store. It means that
x + y = 16
A bird has 2 feet and a cat has 4 feet. The store manager says that there are 42 animal feet in the store. It means that
2x + 4y = 42 - - - - - - - - - - - - 1
Substituting x = 16 - y into equation 1, it becomes
2(16 - y) + 4y = 42
32 - 2y + 4y = 42
- 2y + 4y = 42 - 32
2y = 10
y = 10/2 = 5
x = 16 - y = 16 - 5
x = 11
Let f(x) = -2x + 4 and g(x) = -6.0 – 7. Find f(x) – g(x).
Please show your work and explain steps! GIVING BRAINLIEST!!
Answer:
-2x + 3
Step-by-step explanation:
f(x) - g(x)
(-2x + 4) - (-6.0 - 7)
-2x + 4 - (-6.0) - 7
-2x + 4 + 6.0 - 7
-2x + 10 - 7
-2x + 3
In your class, you have scores of 66, 74, 71, and 81 on the first four of five tests. To get a grade of Upper C, the average of the first five tests scores must be greater than or equal to 70 and less than 80. a. Solve an inequality to find the least score you can get on the last test and still earn a Upper C. b. What score do you need if the fifth test counts as two tests?
Answer:
A score of greater than equal to 128 and less than 188 will get a grade of Upper C
Step-by-step explanation:
We are given the following in the question:
Scores:
66, 74, 71, 81
Let x be the score on fifth test.
[tex]\text{Average} = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}[/tex]
To get a grade of Upper C, the average of the first five tests scores must be greater than or equal to 70 and less than 80.
[tex]70 \leq \text{Average} < 80[/tex]
The fifth test counts as two tests.
Putting the values we get:
[tex]70 \leq \dfrac{66 +74+71 + 81+ x}{6} < 80\\\\420 \leq 292 + x < 480\\420 -292 \leq x < 480 - 292\\128 \leq x < 188[/tex]
Thus, a score of greater than equal to 128 and less than 188 will get a grade of Upper C
To earn an Upper C, solve an inequality with the average test scores. If the fifth test counts as two tests, the formula changes. Solve the new inequality to find the score needed.
Explanation:To find the least score you can get on the last test and still earn an Upper C, you need to solve the inequality:
(66 + 74 + 71 + 81 + x)/5 ≥ 70
(66 + 74 + 71 + 81 + x)/5 < 80
Solving this inequality will give you the range of scores you can get on the last test. If the fifth test counts as two tests, you can use the weighted average formula:
((66 + 74 + 71 + 81) + 2x)/7 ≥ 70
((66 + 74 + 71 + 81) + 2x)/7 < 80
Solving these inequalities will give you the score you need on the last test.
Learn more about Solving inequalities here:https://brainly.com/question/34745580
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