Help anyone
8th grade math need it asap

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)

Answer:

the answer will be [-3/4,1/2]

Step-by-step explanation:

Answer: D

Step-by-step explanation:

Graph D shows the car increasing speed over time, then, the flat line shows the car remains at a constant speed. In order for the scenario to apply, there needs to be a line parallel to the x-axis which shows a speed remaining the same over a given amount of time. D is the only graph which has this feature, thus this graph displays the scenario.

Answer:

No

Step-by-step explanation:

30% of $75 is $22.50 (0.3×75=22.5)

$75+$22.50=$97.50, not $100

So, the store did not mark up the price by 30% because the original price ($75) plus 30% more does not equal $100.

Answer:

no

Step-by-step explanation:

Answer:

-20/3

Step-by-step explanation:

here x=5 and y=2 then put the value and get answer.

Answer: B

Step-by-step explanation: put the points on a graph

Answer:

noooooooooooooooooooooooooooooooooooooooooooo

Step-by-step explanation:

Answer:

57.14%

Step-by-step explanation:

To convert any fraction to a percentage you need to multiply it by 100

So,

4/7*100= 57.14 (round it off to two decimal places as the question states)

Answer:

=-15

Step-by-step explanation:

3c

3(-5)

3×-5

=-15

Answer:

x=6

Step-by-step explanation:

5tgghjkli

Answer:

Step-by-step explanation:

The paths crossed at when the height are equal i.e when f(x) = g(x)

Given

f(x)=−x^2+2x+4

g(x) = 2x

IF f(x) = g(x), then;

−x^2+2x+4 = 2x

−x^2+2x+4 - 2x = 0

−x^2+4 = 0

-x^2 = -4

x^2 = 4

x = ±√4

x = 2 and -2

Time cannot be negative

Hence x = 2

The path crossed after 2 seconds

Answer:

122º

Step-by-step explanation:

The interior angles of a heptagon add to 900º. We can write an equation and solve:

Now that we know x, we can find the measure of ∠B:

Answer:

Market economy

Step-by-step explanation:

Once again this is because they are changing their prices and items for sale because of the changes in market.

Answer:

[tex]x = 7.142(appx)[/tex]

Step-by-step explanation:

[tex]14x + 18 = 118[/tex]

[tex] = > 14x = 118 - 18 = 100[/tex]

[tex] = > x = \frac{100}{14} = \frac{50}{7} = 7.142(appx)[/tex]

Answer:

It might be 1,050. Also can't believe thats a college question-

It was very easy to solve! Help from an 8th grader here.

Step-by-step explanation:

The smallest four-digit number that is divisible by each of the four smallest prime numbers is 1050.

The divisibility rule states that " Divisible By, implies that when two numbers are divided, the result would be a whole number.

The four smallest prime numbers are 2, 3, 5, and 7.

To find the smallest four-digit number that is divisible by each of these numbers, we can start by finding the least common multiple (LCM) of these numbers. The LCM of a set of numbers is the smallest number that is divisible by all of the numbers in the set.

To find the LCM of 2, 3, 5, and 7, we can start by listing the prime factorization of each number:

2 = 2 x 1

3 = 3 x 1

5 = 5 x 1

7 = 7 x 1

Then, we can find the LCM by taking the highest power of each prime that appears in any of the numbers:

LCM(2, 3, 5, 7) = 2¹ x 3¹ x 5¹ x 7¹  = 210

Since we want the "smallest 4-digit number", then it is:

210 x 5 =1050

Therefore, each of the four lowest prime numbers may be divisible by the smallest four-digit number, which is 1050.

Learn more about the divisibility rule here:

brainly.com/question/10703980

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Answer:

Please Mark as Brainliest!!!!!!

Step-by-step explanation

In an auditorium, there are 21 seats in the first row and 29 seats in the second row. The number of seats in a row continues to increase by 8 with each additional row. How would you find the 100th row?

We can take this as an arithmetic sequence, as the seats in next row is calculated by adding 8 to previous row

So here common difference will be 8

the first term is 21

the arithmetic sequence is given by:

Putting the values of a1 and d

for 100th row,

Putting n=100

3. The sequence 6, 18, 54, 162, … shows the number of pushups Kendall did each week, starting with her first week of exercising.

Give the rule you would use to find the 20th week.

Given sequence is:

6, 18, 54, 162, …

we can see that the common difference is not same so we will find the common ratio

The given sequence is a geometric sequence as are the same for consecutive terms

The geometric sequence is given by:

Hence,

2. Seats in 100th Row = 813

3. Rule is:

Keywords: Sequence, ratio

Answer:

see explanation

Step-by-step explanation:

The sequence is

22, 28, 34, ....

Since there is a common difference of 6 the sequence is arithmetic with n th term

[tex]a_{n}[/tex] = a₁ + (n - 1)d

a₁ is the first term and d the common difference

Here a₁ = 22 and d = 6, then

[tex]a_{n}[/tex] = 22 + 6(n - 1) = 22 + 6n - 6 = 6n + 16

Equate to 100 and solve for n

6n + 16 = 100 ( subtract 16 from both sides )

6n = 84 ( divide both sides by 6 )

n = 14

Thus the 14 th row has 100 seats

Answer:

3.27*10^22

Step-by-step explanation:

Given the expression 9.6x10^85/3x10^63, we are to write it on scientific notation as shown:

9.6x10^85/3x10^63

= (9.8/3) * (10^85/10^63)

= (9.8/3)  * 10^{85-63}

= (9.8/3) *10^22

= 3.27 *10^22

Hence the expression in scientific notation is  3.27*10^22

Answer:

a

Step-by-step explanation:

a

Answer:

0.25

Step-by-step explanation:

3 white counters and 1 black counter,

3+1 = 4

the chances of you choosing the black counter is 1/4

1/4 can also be written as 0.25.

Answer:

The probability of choosing a black counter is 0.25.

Also the picture is attached for the mark on scale.

Step-by-step explanation:

Probability is the likeliness of occurrence of an event.

Given

There are three white and 1 black counter in the bag which means our sample space contains 3+1 = 4 elements

n(S) = 4

Let B be the event that the drawn out counter is black. As there is only one black counter

n(B) = 1

The probability of choosing a black counter is:

[tex]P(B) = \frac{n(B)}{n(S)}\\P(B) = \frac{1}{4} = 0.25[/tex]

Hence,

The probability of choosing a black counter is 0.25.

Also the picture is attached for the mark on scale.

Answer:

Since the computed value of t= -4.654 does not fall in the critical region we therefore accept the null hypothesis . We conclude that there is sufficient evidence to indicate a difference in the means time served for fraud is less than that for firearms offenses.

Step-by-step explanation:

Fraud                                        Firearm

15.2      9.2                              20.1          15.7

11.2       15.8                             20.4          9.8

7.2         5.2                             13.1           13.5

7.7         4.9                            20.7           23.1

7.4        9.8                            10.4            22.2            

∑ 93.6                                             169                    

Fraud  (X1i)²                                      Firearm(X2j)²

231.04      84.64                           404.01          246.49

125.44      249.64                          416.16          96.04

51.84        27.04                            171.61           182.25

59.29       24.01                            428.49           533.61

54.76        96.04                            108.16           492.84

∑1003.79                                                  3079.66          

We formulate the null and alternative hypothesis as

H0: μ1 - μ2 ≤ 0 i.e. the fraud meantime is less than that for firearms offenses.

Ha: μ1-  μ2  > 0  i.e. the fraud meantime is greater than that for firearms offenses.

We set the significance level at ∝= 0.01

The test statistic, if  H0 is true , is

t=  x1`1- x`2/ Sp√1/n1+ 1/n2

which has a student t- distribution with ν= n1+ n2 -2 = 18 degrees of freedom

The critical region consists of all t- values which are greater than or equal to  t> t(0.01)(18)= 2.522

Computations :

X1`= ∑X1i/n1 = 93.6/10= 9.36

X2`=∑X2j/n2=169/10 = 16.9

∑( X1i- x`1)² = ∑X1i²- (∑X1i)²/n1

= 1003.79 - 876.096/10

= 100.379- 87.6096

=12.7694

∑( X2j- x`2)² = ∑X2j²- (∑X2j)²/n2

= 3079.66 - 28561/10

= 3079.66- 2856.1

=223.56

Sp²= 12.7694+223.56/18= 13.129

Sp = √13.129 =3.623

t= 9.36-16.9/ 3.623√0.1+0.1

t= -7.54/ 1.62

t= -4.654

Conclusion: Since the computed value of t= -4.654 does not fall in the critical region we therefore accept the null hypothesis . We conclude that there is sufficient evidence to indicate a difference in the means time served for fraud is less than that for firearms offenses.

The meantime served for fraud is less than that for firearms offenses.

Answer: 579.36 km/h miles  to kilometers

  1296 meters to kilometers

Step-by-step explanation: couldnt  tell what you meant so both

Answer: 75.1

Step-by-step explanation:

Answer:

86.0*

Step-by-step explanation:

i am not 100% sure

Answer:

D

Step-by-step explanation:

Answer:

50.27

Step-by-step explanation:

Answer:

4 operations b/c thats how many is in the box

them you do addition using PEMDAS( perinthasis exponets multiplication division addition subtraction hope this is helpful

Step-by-step explanation:

Answer:

What is the question?? The question is not there

Answer:

129870 did not vote or voted for someone else.

Step-by-step explanation:

I don't know what your asking

An equation that represents the relationships between the time x and the distance y is y = 40x.

Equations whose variables have a power of one are called linear equations. One example with one variable is where ax+b = 0, where a and b are real values and x is the variable.

Given:

An eagle flies 40 miles per hour.

An equation that represents the relationships between the time x and the distance y:

Here, x and y are the variables.

So, the equation,

y = 40x.

Therefore, y = 40x is the required equation.

To learn more about the linear equation;

https://brainly.com/question/29739212

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