Answer: If the a and b of your formula mean how many hours it takes each
person, like a = 2 and b = 1, then the formula gives 3/2 or 1 hour and
30 minutes. This is not reasonable, since one of the painters alone
could do it in 1 hour.
Actually, your formula is UPSIDE DOWN. It should be (a*b)/(a+b).
Here's why.
Let h be the number of hours it takes for the two of them to do it
together. The first person could do it all in a hours, but can paint
only a fraction of the wall working h hours. Assuming a constant rate
of painting, that fraction is h/a. That is, the first painter will
paint h/a of the wall in h hours.
Similarly, the second painter will paint h/b of the wall in that time.
So, when will they be done? When the whole wall is painted, which
happens whenever those 2 fractions add up to 1.
You need to solve the following equation:
(h/a) + (h/b) = 1
h*b + h*a = a*b Multiplying through by a*b
h*(b+a) = a*b Factoring out h
h = (a*b)/(a+b) Dividing both sides by b+a
Okay, now say 3 painters could do it in a hours, b hours or c hours,
respectively. Let h be the number of hours they all must work to get
it all painted. The first painter finishes h/a of the wall in that
amount of time. The other 2 painters manage to paint h/b of the wall
and h/c of the wall in that time. Since h is the time to finish the
job, all 3 of these fractions must add up to the whole wall, or 1.
So you have the equation:
h h h
--- + --- + --- = 1
a b c
Solve this for h (start by multiplying through by a*b*c) and you will
get the generalized formula for 3 painters. It's not the formula you
wrote above but I think you can finish it off.
(I hope this helps. I'm sorry if it's wrong)
Please help me
Find the value of x.
Answer:
d: x = -8
Step-by-step explanation:
40 + 65 + x + 83 = 180 (sum of internal angles of a triangle)
x = 180 - 40 - 65 - 83
x = -8
HELP PLEASE!!
What is Y
what is the correct factorization of x^2 - 2x - 15?
Answer:
Step-by-step explanation:
x2 - 2x - 15
x2 - 5x + 3x - 15
x(x - 5) + 3(x - 5)
(x - 5) and (x + 3) are the factors
convert 53 yards per hour into inches per day
1 yard = 36 inches.
53 yards per hour x 36 inches per yard = 1908 inches per hour.
1 day = 24 hours.
1908 inches per hour x 24 hours = 45,792 inches per day.
Angel Sanchez has 10 books on a shelf; 5 mysteries, 4 science fiction books, and 1 biography. Determine the probability of each situation below.
a) Selecting one biography and then one mystery, with replacement
b) Selecting one biography and then one mystery, without replacement
a) The probability of selecting one biography and then one mystery, with replacement, is 17
(Type an integer or a simplified fraction)
Answer:
a) 1/10 x 5/10 = 1/20
b) 1/10 x 5/9 = 1/18
Step-by-step explanation:
a) Probability of selecting one biography and then one mystery, with replacement: 1/20
b) Probability of selecting one biography and then one mystery, without replacement: approximately 0.0556 or 5.56%.
The probability of each situation can be calculated as follows:
a) Selecting one biography and then one mystery, with replacement:
With replacement means that after each selection, the book is put back on the shelf before the next selection.
The probability of selecting the biography first is 1 out of 10 books (since there is 1 biography out of 10 books).
The probability of selecting the mystery book next is 5 out of 10 books (since there are 5 mysteries out of 10 books).
The overall probability is the product of the individual probabilities:
Probability = (1/10) * (5/10) = 1/20
So, the probability of selecting one biography and then one mystery, with replacement, is 1/20.
b) Selecting one biography and then one mystery, without replacement:
Without replacement means that after each selection, the book is not put back on the shelf before the next selection.
The probability of selecting the biography first is still 1 out of 10 books.
However, after selecting the biography, there are now 9 books left on the shelf, and the probability of selecting a mystery is 5 out of 9 books (since there are 5 mysteries out of the remaining 9 books).
The overall probability is the product of the individual probabilities:
Probability = (1/10) * (5/9) ≈ 0.0556 or 5.56%
So, the probability of selecting one biography and then one mystery, without replacement, is approximately 0.0556 or 5.56%.
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Hurry please
I need the answer to this one in 2 minutes
Answer:
125
Step-by-step explanation:
45 ÷9=5
5² or 5×5=25
25×5=125
Hope this helps!
Answer:
I THINK ITS
Step-by-step explanation:
5x(2025 ÷81)
5x25
125
The cafeteria offers two snack options as shown in the table. Out of 18
students, 8 students choose Option B and the rest choose Option A. If the
total cost of option A is the same as the option B, what is the price of a
carton of milk?”
Answer:69,420
Step-by-step explanation:
9+10=21
The price of a carton of milk is $1.00
The given parameters are:
Number of students, n = 18Option A = 8Since 8 chose option A, it means that 10 would choose option B
So, the equation that represents when both price are equal is:
[tex]8(2x + 0.5) = 10(x + 1)[/tex]
Where
2x + 0.5 represents the unit price of option A
x + 1 represents the unit price of option B
Open the brackets
[tex]16x + 4 = 10x + 10[/tex]
Collect like terms
[tex]16x - 10x = 10 - 4[/tex]
Evaluate the like terms
[tex]6x = 6[/tex]
Divide
[tex]x = 1[/tex]
Hence, the price of a carton of milk is $1.00
Read more about equivalent equations at:
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(4,8), m=5 need a step by step answer please
Answer:
8=4x+5
Step-by-step explanation:
Slope-intercept form: y=mx+b
1. Identify your terms:
x: 4
y:8
b/slope: 5
2. Solution:
8=4x+5
3.5x + 4y if x=3 and y = 7
4 6x-42 if x =4 and 2
5.83 +4 ry if y=2 and y= 100
3,5× 3 + 4 × 7 =3 8,5
46*4-42=143 46* 2- 4 2= 50
5,83+4*2=13,83 5,83+4*100=405,83
pweese help!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
D
Step-by-step explanation:
The federal government would like to test the hypothesis that the average age of men filing for Social Security is higher than the average age of women with the following data: Men Women Sample mean 64.5 years 63.6 years Sample size 35 39 Population standard deviation 3.0 years 3.5 years If Population 1 is defined as men and Population 2 is defined as women, the 90% confidence interval for the difference in population means is (closest to) ________. Group of answer choices
Answer:
The 90% confidence interval is [tex] -0.3433< \mu_1 - \mu_2 < 2.1433[/tex]
Step-by-step explanation:
From the question we are told that
The sample mean for men is [tex]\= x_1 = 64.5 \ years[/tex]
The sample mean for women is [tex]\= x_2 = 63.6 \ years[/tex]
The sample size for men is [tex]n_1 = 35[/tex]
The sample size for women is [tex]n_2 = 39[/tex]
The standard deviation for men is [tex]s_1 = 3.0[/tex]
The standard deviation for women is [tex]s_2 = 3.5[/tex]
From the question we are told the confidence level is 90% , hence the level of significance is
[tex]\alpha = (100 - 90 ) \%[/tex]
=> [tex]\alpha = 0.10[/tex]
Generally from the normal distribution table the critical value of [tex]\frac{\alpha }{2}[/tex] is
[tex]Z_{\frac{\alpha }{2} } = 1.645 [/tex]
Generally the standard error is mathematically represented as
[tex]SE = \sqrt{\frac{s_1^2 }{n_1} + \frac{s_2^2}{n_2} }[/tex]
=> [tex]SE = \sqrt{\frac{3^2 }{35} + \frac{3.5^2}{39} }[/tex]
=> [tex]SE = 0.7558[/tex]
Generally the margin of error is mathematically represented as
[tex]E = Z_{\frac{\alpha }{2} } * SE[/tex]
=> [tex]E = 1.645 * 0.7558[/tex]
=> [tex]E = 1.2433[/tex]
Generally 90% confidence interval is mathematically represented as
[tex](\= x_1 - \= x_2) -E < \mu_1 - \mu_2 < (\= x_1 - \= x_2) -E [/tex]
=> [tex](64.5 - 63.6) -1.2433< \mu_1 - \mu_2 <(64.5 - 63.6) +1.2433[/tex]
=> [tex] -0.3433< \mu_1 - \mu_2 < 2.1433[/tex]
sophias car wash llc specializes in detaling cars. For a pick up truck, sophia charges 30 dollars she also charges a rate of 4 dollars per hour. if sophia charged you 42 dollars how many hours did it take for her to detail your truck
Answer:
3 Hours
Step-by-step explanation:
If we subtract 30 dollars from the initial 42, we are left with 12 dollars. Then all we have to do is do 12/4 to get 3 hours of work :D
y = -8x – 3
x+y=7
Is (3, 4) a solution of the system?
Answer: the answer is no :)
I need the answer ASAP
Answer:
the are is 14
brainliest??
Step-by-step explanation:
Answer:
48ft
Step-by-step explanation:
Hope this helps. :)
Casey walked 2.1 miles to the grocery store. She then walked 0.5 miles to the post office and 0.8 miles to work. How far did she walk in total? Convert your answer into kilometers.
Answer:
3.4 miles and 5.472 kilometers
Can someone help with this Problem? It is about Evaluating expressions using properties of exponents. Would help a lot. Attachment below
9514 1404 393
Answer:
1/192
Step-by-step explanation:
The properties of exponents useful here are ...
a^0 = 1 . . . . for a ≠ 0
a^-b = 1/a^b
__
[tex]4^{-2}\cdot 12^{-1}\cdot 12^0=\dfrac{1}{4^2}\cdot\dfrac{1}{12}\cdot 1\\\\=\dfrac{1}{16\cdot12}=\boxed{\dfrac{1}{192}}[/tex]
I need help please and thanks
Answer:
68 degrees
Step-by-step explanation:
1 & 6 have to equal 180. Therefore, if 1 is 112 then you take 180-112. Then you get 68 degrees.
Answer:
Angle 6 would be 68 degrees
Step-by-step explanation:
Angles 1, 3, 5, and 7 all equal 112. you would subtract 112 from 180 to get the measurement for angles 2, 4, 6, and 8
!!HELP!! What is q times 10?
Answer:
Q10. You just put them together because it's multiplying of a letter and a number
**I thought I answered this question yesterday, is this a deja vu or something**
IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. Using the empirical rule, determine the interval that would represent the middle 95% of IQ scores.
Answer:
About 95% of individuals have IQ scores in the interval 100 ± 2 ( 15 ) = [ 70 , 130 ] .
Step-by-step explanation:
hope this helps
Merry Christmas please help
Answer:
All Of The Number At The Top
Step-by-step explanation:
Like Said, The Tables Functions f
So, Basically It's A Challenge,
All Of The Numbers In Row X From Above Table
I Hope You Found This Answer Helpful
Good Day
You'll Get 100% Don't Stress It✨
By: LocalLesMara
A group of students are standing in rows. There are as many students in a row as there are rows. If there are 64 students in the group, how many students are standing in pach row?
A. 4
B 6
C. 8
D 12.
Answer:
B..im pretty sure
Step-by-step explanation:
First it cant be D because 12 x __ = 64. There is no whole number multiplied by 12 that equals 64. So cross that out. then it's not B because 6 x ___ = 64. So also cross that out. the only thing u have left is 4 and 8. Then u can cross out A because the group of students has to be the same number of rows. Which is 8 x 8 aka B. The answer is B
Answer:
B
Step-by-step explanation:
How is the space between consecutive whole numbers divided on the number line?
O into halves
O into fifths
O into sixths
O into sevenths
C. INTO SIXTHS
I LITRALLY JUST TOOK THE TEST ON EDGE. SO YOU CAN TAKE MY WORD FOR IT
I HOPE I WASNT TOO LATE. IF I WAS, SORRY
The number of grids or intervals on the given number line between any two consecutive whole numbers is six thus option (C) is correct.
What is a number line?In mathematics, a number line is a straight line containing numbers arranged at equal segments or periods throughout its duration.
A horizontal number line is the most common representation and can be extended infinitely in any direction.
As per the given number line,
Since 1 is a whole number and 2 is also a whole number.
The number of intervals between 1 and 2 is 6.
Thus, between consecutive whole numbers divided on the number line is 6.
Hence "The number of grids or intervals on the given number line between any two consecutive whole numbers is six".
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Arthemeatic sequence
Answer:
14
Step-by-step explanation:
its going down by 11
If 12 cookies cost $3 how much would it be for 9 cookies
can someone help me with this
Answer:0.98
hope this helps have a good day
Step-by-step explanation:
i need a step by step explanation
Answer:
1/2c-4
Step-by-step explanation:
First, you distribute the fraction on the outside to the numbers inside of the parenthesis. So, you distribute 1/2 to c, which gives you 1/2 x c = 1/2c. Then, you distribute the 1/2 to -8, which gives you 1/2 x -8 = -4. You combine these expression together and get your final answer as 1/2c-4.
The square below represents one whole.
Express the shaded area as a fraction, a decimal, and a percent of the whole.
Fraction:
Decimal:
Percent:
Answer:
Below.
Step-by-step explanation:
10 rectangles, 2 are shaded in.
Fraction: 1/5
Decimal: 0.2
Percent: 20%
Question 1 (5 points)
Saved
(01.01 LC)
Which of the following is a rational number? (5 points)
square root of 2, square root of 3, square root of 4, and square root of 5
Question 1 options:
1)
square root of 2
2)
square root of 3
3)
square root of 4
4)
square root of 5
Answer:
Square root of 4 is ans
Step-by-step explanation:
Answer:
4) square root of 4
Step-by-step explanation:
Grade 4 Mathematics- Checkpoint #3
In 2008 the total number of cell phone users in Indonesia was about 140,578,000. Which expression has the same value as 140,578,000?
Answer:
2^4 x 5^3 x 70289
Step-by-step explanation:
16 x 125 x 70289=140,578,000
What is the equation relating x and
y together?
y
1
2
3
4
5
25
23
21
19
17
y=-2x + [?]
Answer:
ommmm I have no idea Butt 1 of my fav numb is 17 so pick that