5 bricklayers can lay a total of 50 bricks in 30 minutes. How many bricklayers will
be required to lay a total of 60 bricks in 18 minutes?
Answer:
First look at the number of bricks alone.
Going from 50 bricks to 60 bricks is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 60/50
Next look at the time alone.
Going from 30 minutes to 20 minutes is more work, thus it will require more people. The number of people would be the ratio of the 2. Since the number must be larger, you know the numerator must be the larger of the 2 numbers, so you get 30/20
Now you can just multiply everything.
= 5*60/50*30/20
= 5*6/5*3/2
= 90\10
= 9.
The curriculum director in a large 3 points school district wants to determine the difference between the proportion of high school juniors who are enrolled in AP classes and the proportion of high school seniors who are enrolled in AP classes. She randomly selects 75 seniors and 70 juniors. Twenty-six of the seniors are enrolled in AP classes and 15 of the juniors are enrolled in AP classes. A 90 percent confidence interval for the difference between the proportion of seniors and juniors who are enrolled in AP classes is calculated. Which statement is not true?
A) The critical value used is 1.645.
B) The standard error of the difference is 0.074
C) The 90% interval was constructed using a method that results in intervals which capture the true difference in the proportion of seniors who are enrolled in AP classes and the proportion of juniors who are enrolled in AP classes 90% of the time.
D) She can be 90% confident that the true difference between the proportion of seniors who are enrolled in AP classes and the proportion of juniors who are enrolled in AP classes is between 0.0112 and 0.2535 students.
E) There is a 90% chance that the true difference between the proportion of seniors who are enrolled in AP classes and the proportion of juniors who are enrolled in AP classes is between 0.0112 and 0.2535
Answer:
C) The 90% interval was constructed using a method that results in intervals which capture the true difference in the proportion of seniors who are enrolled in AP classes and the proportion of juniors who are enrolled in AP classes 90% of the time.
Step-by-step explanation:
x% confidence interval -> Options c, d and e:
A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.
This means that options d and e are correct, while option c is not true.
Option a -> Critical Value:
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].
This means that option A is true.
Estimate of the standard error:
Before building the estimate, we should take a look at the central limit theorem and subtraction of normal variables.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
Subtraction between normal variables:
When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.
26 of 75 seniors:
This means that:
[tex]p_s = \frac{26}{75} = 0.3467, s_s = \sqrt{\frac{0.3467*0.6533}{75}} = 0.055[/tex]
15 of 70 juniors:
This means that:
[tex]p_j = \frac{15}{70} = 0.2143, s_j = \sqrt{\frac{0.2143*0.7857}{70}} = 0.049[/tex]
Estimate of the standard error:
[tex]s = \sqrt{s_s^2 + s_j^2} = \sqrt{0.055^2 + 0.049^2} = 0.074[/tex]
Thus option b is correct.
Carmen is painting a rectangular wall that is 9 feet long and 14 feet wide. What is the area that Carmen will paint?
o
A 23 square feet
B. 46 square feet
o
C. 63 square feet
D. 126 square feet
PLEASE HELP
find the equation of the straight line which has a gradient of 3 and passes through the point (-1, 3)
Answer:
y=3x+6
Step-by-step explanation: 3=3(-1)+b
3=-3+b
+3 +3
6=b
X-7;x=23. I NEED help
Answer:
x-7=16
Step-by-step explanation:
if x=23 substitute it in the equation
so; 23-7=?
23-7=16
your answer would be 16
Answer:
my dad never returned home
find the area of this figure
Answer:
164
Step-by-step explanation:
5×8×2=80
7×12=84
84+80=164
Solve for x.
x = [?]
4x - 16
2x + 16,
Answer:
Solution given:
4x-16+2x+16=180{linear pair are supplementary]
6x=180
x=180/6
x=30
is a required answer.
Find the sum of each of the following polynomials.
a) [tex]x^3+5x^2+2, 3x^2-4x+7[/tex]
b) [tex]2x + 5x^3-2x^2+7, 9+4x-5x^2-2x^3[/tex]
c) [tex]5x^3+2x^2+4, 2x^2+7x-5, 7-5x^2 +3x-4x^3[/tex]
d) [tex]2x^4-3x^2+4x^3-5, 9x^2-7x^3-2x^4, 7-x+3x^4[/tex]
Answer:
[tex](a)\ Sum = x^3+8x^2-4x+9[/tex]
[tex](b)\ Sum =3x^3-7x^2+6x +16[/tex]
[tex](c)\ Sum = x^3-x^2+10x+6[/tex]
[tex](d)\ Sum = 3x^4 -3x^3+ 6x^2-x+2[/tex]
Step-by-step explanation:
Required
Sum of the polynomials
[tex](a)\ x^3+5x^2+2, 3x^2-4x+7[/tex]
[tex]Sum = x^3+5x^2+2+3x^2-4x+7[/tex]
Collect like terms
[tex]Sum = x^3+5x^2+3x^2-4x+2+7[/tex]
[tex]Sum = x^3+8x^2-4x+9[/tex]
[tex](b)\ 2x + 5x^3-2x^2+7, 9+4x-5x^2-2x^3[/tex]
[tex]Sum =2x + 5x^3-2x^2+7+ 9+4x-5x^2-2x^3[/tex]
Collect like terms
[tex]Sum =5x^3-2x^3-2x^2-5x^2+4x+2x +7+ 9[/tex]
[tex]Sum =3x^3-7x^2+6x +16[/tex]
[tex](c)\ 5x^3+2x^2+4, 2x^2+7x-5, 7-5x^2 +3x-4x^3[/tex]
[tex]Sum = 5x^3+2x^2+4+ 2x^2+7x-5+ 7-5x^2 +3x-4x^3[/tex]
Collect like terms
[tex]Sum = 5x^3-4x^3+2x^2+ 2x^2-5x^2+7x+3x-5+ 7 +4[/tex]
[tex]Sum = x^3-x^2+10x+6[/tex]
[tex](d)\ 2x^4-3x^2+4x^3-5, 9x^2-7x^3-2x^4, 7-x+3x^4[/tex]
[tex]Sum = 2x^4-3x^2+4x^3-5+ 9x^2-7x^3-2x^4+ 7-x+3x^4[/tex]
Collect like terms
[tex]Sum = 2x^4-2x^4+3x^4 +4x^3 -7x^3-3x^2+ 9x^2-x-5+ 7[/tex]
[tex]Sum = 3x^4 -3x^3+ 6x^2-x+2[/tex]
How to solve Solve 3!
Answer:
by solving 3
Step-by-step explanation:
PLEASE ANSWER ASAP WILL MARK BRAINLIEST!!
Compare the effects of increasing biodiversity and overpopulation on an ecosystem.
a.) An increase in biodiversity is not good for the ecosystem because it provides a variety of species. Overpopulation is good for the ecosystem because there are more individuals.
b.) An increase in biodiversity is good for the ecosystem because it provides a variety of species. Overpopulation is not good for the ecosystem because there are more individuals.
c.) Neither increasing biodiversity nor overpopulation are good for the ecosystem because they provide a variety of species and more individuals.
Answer:
B
Step-by-step explanation:
Overpopulation causes killing of animals
Answer:
B) An increase in biodiversity is good for the ecosystem because it provides a variety of species. Overpopulation is not good for the ecosystem because there are more individuals
Step-by-step explanation:
The bigger the ecosystem is, the more producers there are, which makes more consumers.
If there are too many consumers, then more populations will go extinct.
(I also had this on my quiz, ill tell you down below if I got it right)
EDITED!!: It was correct!! Have a nice day y'all! :)
If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to y from the first equation is substituted into the second equation.
6x − y = 1
4x − 3y = −11
Select one:
a. 4(−6x + 1) − 3y = −11
b. 4(6x + 1) − 3y = −11
c. 4x − 3(6x − 1) = −11
d. 4x − 3(−6x − 1) = −11
Answer:
6x − y = 1 -------(1)
4x − 3y = −11 ------(2)
(1)×3
18x - 3y =3 ------(3)
4x − 3y = −11 ------(2)
(3)+(2)
18x - 3y + ( 4x - 3y) = 3+(-11)
d. 4x − 3(−6x − 1) = −11 is the answer.
PLZZZ HELP!!! Brainliest to whoever can help!!! T^T
Answer:
I think it B
Step-by-step explanation:
Answer:
C
Step-by-step explanation:
h=2x^2
b=5x^2+4x
we know that
area of triangle (A)=1/2×b×h
=1/2×2x^2×(5x^2+4x)
=x^2(5x^2+4x)
=5x^4+4x^3 square units
nelda needs a wrench to fix her bike a 5/8 inch wrench was too big a 1/4 inch wrench what's the small which of the following would be bigger than 1/4 Inch wrench in smaller than the 5/8 inch wrench
Answer: 1/2
Step-by-step explanation:
The graph of the invertible function h is shown on the grid below. What is the value of h -1(-4)
Answer: ℎ + 4
Step-by-step explanation:
h − 1 (−4)
ℎ + 4
Answer:
The answer is h^-1(-4)= -2
Step-by-step explanation:
This answer was pulled from Khan Academy.
50 POINTS !!
PLEASE HELP
EXPLAIN HOW YOU GOT IT !!!!
ILL GIVE BRAINLIEST TO THE RIGHT ANSWERS.
Answer:
Step-by-step explanation:
Hope this helps u!!
Abe is going to plant 54 oak trees and 27 pine trees. Abe would like to plant the trees in rows that all have the same number of trees and are made up of only one type of tree. What is the greatest number of trees Abe can have in each row?
HELP!
Answer:
9
Step-by-step explanation:
The GCF between 54 and 27 is nine.
A car traveled 11.5 miles in 15 minutes. How many miles per hour was it traveling?
Answer:
46 miles per hour
Step-by-step explanation:
ِAn hour has 60 minutes. In 60 minutes, there is four 15 minutes (4*15 = 60).
So, if it travelled 11.5 miles in 15 minutes, in an hour, it travelled 11.5 * 4 = 46 miles per hour.
The miles per hour he was travelling is 46 miles.
What is the miles per hour travelled?
The first step is determine the average speed. Average speed is the total distance travelled per time.
Average speed = total distance / total time
11.5 / 15 = 0.766667 miles / per minutes
Miles travelled = average speed x time
Miles travelled = 0.766667 x 60 = 46 minutes
To learn more about average speed, please check: https://brainly.com/question/21734785
What is the y-intercept in the equation y = 3x + 4 ?
Answer:
4 is the y-intercept
Step-by-step explanation:
Here's a photo the explains the equation
Answer:
[tex]The ~y-intercept ~is~ (0,4)[/tex]
------------------------
hope it helps...
have a great day!!
1. It is a four-digit whole number.
2. Each of its digits is even.
3. Each of its digits is different.
4. The sum of its one digit and its hundreds digit is 10.
5. The sum of its tens digit and its thousand digit is 10.
6. It is greater than 7000.
7. It is divisible by 4.
8. The numeral O is not one of its digits.
9. It is divisible by 8.
10. Its hundreds digit is 6.
Answer:
8624
Step-by-step explanation:
let's write four blanks to represent the number _ _ _ _
by rule #10 we can fill in one digit
_ 6 _ _
using rule 4 we can wee that the ones digit is 4
_ 6 _ 4
We know that the thousand's digit has to be an even number greater than 7 (which leaves 8 only)
8 6 _ 4
using rule 5 we can see that the tens digit is 2
get get
8624
A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by the given equation. Using this equation, find the time that the rocket will hit the ground, to the nearest 100th of second.
y=-16x^2+124x+127
Answer:
Step-by-step explanation:
so when the height is zero, that's when the rocket hits the ground. The equation will have two zeros, but one would be for a negative time, or before the rocket is launched. so we only one the one after the rocket is launched.
use the quadratic formula to solve for x ( which is time)
-124 +- sqrt [ [tex]124^{2}[/tex] - 4*(-16)*(127) ] / 2 (-16)
-124 +- sqrt [15376 + 8128 ] / -32
-124 +- sqrt [23504 ] / -32
-124 +- 153.310 / -32
if we take the positive part it will become the negative time so skip that one try the negative part 1st
-124 - 153.310 / -32
-277.310 / -32
8.6659 seconds to hit the ground. ( time of flight) aka TOF
8.67 seconds ( rounded to nearest 100th)
A student measures the air pressure inside her bicycle tires before and after she goes on a long bicycle ride. What will she most likely observe?
Answer:
She will see that the pressure went up, not down!
Step-by-step explanation:
1. In a closed system, The volume inside the tire shouldn't change much (the losses will be small)
2. For a closed system, the Pressure inside a bicycle tire will increase with the increase of its Temperature
3. In a long bicycle ride, the constant friction of the tire to the ground will heat up the air inside the tire, thus increasing the pressure inside the tire
How to solve 4x - 5 = 2x + 19?
Answer:
x = 12
Step-by-step explanation:
4x - 5 = 2x + 19
First subtract the 2x from 4x.
2x - 5 = + 19
Then add the 5 to the 19.
2x = 24
Divide 24 by 2 in order to get x by itself.
x = 12
The problem solving is on the image, 6th grade
Find the equation that has a slope of -1/8 and passes through the point (0,-4)
A. Y= 1/8x
B. Y=1/4x-4
C. Y=-1/8x-4
Answer:
Option C
Step-by-step explanation:
Given :-
The slope of the line is -1/8The line passes through (0,-4) .And we need to find out the equation of the line .We are here given slope and a point . So we can use the slope point form of the line. As ,
[tex]:\sf\implies m ( x - x_1)= y - y_1 \\\\\sf:\implies \dfrac{-1}{8}(x -0)= y - (-4) \\\\\sf:\implies \dfrac{-x}{8}= y +4 \\\\\sf:\implies \boxed{ \sf\red{y = \dfrac{-x}{8}-4}}[/tex]
Hence the option C is correct.
find the slope of the line that passes through points (-1, -10) and (-1, -2)
Answer:
undefined
Step-by-step explanation:
[tex]\boxed{slope = \frac{y1 - y2}{x1- x2} }[/tex]
☆ (x₁, y₁) is the 1st coordinate and (x₂, y₂) is the 2nd coordinate.
Slope of the line
[tex] = \frac{ - 2 - ( - 10)}{ - 1 - ( - 1)} [/tex]
[tex] = \frac{8}{0} [/tex]
(undefined)
Notice that the 2 points have the same x-coordinate of -1, which means that the line is a vertical line. Vertical lines have an undefined slope.
According to the National Association of Colleges and Employers, the mean salary for a new college graduate is $45,327. A small college wants to know if the mean salary of their most recent graduates is greater than $45,327. A random sample of 10 recent graduates from the small college was selected and the mean and standard deviation of the salary for those graduates was found. With all conditions for inference met, a significance test was conducted and a p-value of 0.045 was obtained. Which of the following statements is the most appropriate conclusion using a significance level of a = 0.05?
(A) There is convincing statistical evidence that the mean salary for all recent college graduates from the small college is greater than $45,327.
(B) There is convincing statistical evidence that the mean salary for the sample of 10 college graduates from the small college is greater than $45,327.
(C) There is not convincing statistical evidence that the mean salary for all recent college graduates from the small college is greater than $45,327
(D) There is not convincing statistical evidence that the mean salary for the sample of 10 college graduates from the small college is greater than $45,327.
(E) There is not convincing statistical evidence that the graduates from this college will always eam more than $45,327.
Answer:
(A) There is convincing statistical evidence that the mean salary for all recent college graduates from the small college is greater than $45,327.
Step-by-step explanation:
According to the National Association of Colleges and Employers, the mean salary for a new college graduate is $45,327. A small college wants to know if the mean salary of their most recent graduates is greater than $45,327.
At the null hypothesis, we test if the mean salary is the expected salary of $45,327, that is:
[tex]H_0: \mu = 45327[/tex]
At the alternate hypothesis, we test if the salary is greater than the expected salary of $45,327, that is:
[tex]H_1: \mu > 45327[/tex]
With all conditions for inference met, a significance test was conducted and a p-value of 0.045 was obtained. Which of the following statements is the most appropriate conclusion using a significance level of a = 0.05?
The p-value of the test if 0.045 < 0.05, which means that there is sufficient evidence to accept the alternate hypothesis, that is, to conclude that the mean salary for all recent college graduates from the small college is greater than $45,327.
This means that the correct answer is given by option A.
HELP ME!!! 4- 5/8 =?
Answer:
27/8
Step-by-step explanation:
1.) 4-5/8
Convert element to fraction
2.) 4 x 8/8-5/8
3.) 4 x 8-5/8
4.) 27/8
An airplane ascended at a rate of
2,000 feet per minute. What is the
altitude of the plane after 15 minutes
Answer:
the altitude of the plane is 30,000 after 15 minutes
Step-by-step explanation:
since the plane goes up 2,000 ft per minute I multiplied 2,000 by 15(the minutes) and got 30,000
6 cm = ______ mm *
50 mm = ______ cm
100 mm=_______cm
20 mm = ______ cm
5kg = ______ g *
800g = _____kg *
6000mg = ______kg *
2lit = _____ml *
75ml = ____lit *
82km = ____m
Answer:
6 cm = __6*10=60____ mm *
50 mm = _[tex] \frac{50}{10} [/tex]__=5___ cm
100 mm=__[tex] \frac{100}{10} [/tex]=10____cm
20 mm = __[tex] \frac{20}{10} [/tex]_=2_____ cm
5kg = _5*1000=5000_____ g *
800g = ____[tex] \frac{800}{1000} [/tex]=0.8___kg
6000mg = ___[tex] \frac{6000}{1000000} [/tex]=0.006___kg *
2lit = _2*1000=2000_ml *
75ml = __[tex] \frac{75}{1000} [/tex]=0.075_lit *
82km = 82*1000=82000__m
The perimeter of a rectangular field is 332 yards. If the length of the field is 92 yd what is the width?
Answer:
The width of the rectangular field is equal to 74 yards.
General Formulas and Concepts:
Algebra I
Equality Properties
Multiplication Property of EqualityDivision Property of EqualityAddition Property of EqualitySubtraction Property of EqualityTerms/Coefficients
Geometry
Perimeter Formula [Rectangle]:
[tex]\displaystyle P = 2l + 2w[/tex]
Step-by-step explanation:
Step 1: Define
Identify given variables.
P = 332 yds
l = 92 yds
Step 2: Find Width
[Perimeter Formula - Rectangle] Substitute in variables:∴ the width of the field is equal to 74 yards.
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Learn more about Geometry: https://brainly.com/question/27795993
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Topic: Geometry