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Ok, so right now you've got me confused. Do you mean that \(7+77+777+7777 = 8500?\) I believe the sum of those four numbers is 8638... Also, what do you mean that "The sum of each group is 85000000, which has a 7 in the hundreds place"?

Note that 7+77+777+7777 is actually equal to 8638

The hundreds place of the sum will be 7.

To see this, we can group the terms of the sum together by their hundreds place:

7 + 77 + 777 + 7777 = 8500

7777 + 77777 + 777777 = 850000

777777 + 7777777 + 77777777 = 85000000

...

The sum of each group is 85000000, which has a 7 in the hundreds place. Since there are 20 groups, the hundreds place of the final sum will also be 7.

Thanks Guest for trying, but it says it's wrong 

Solve for r:
2 - (2 n)/(n + 1) = 2 r

order to isolate r to the left hand side.

2 - (2 n)/(n + 1) = 2 r is equivalent to 2 r = 2 - (2 n)/(n + 1):

2 r = 2 - (2 n)/(n + 1)

Divide both sides by 2:

r = 1 /(n + 1)

Thank you!

Let's start by using algebraic variables to represent the number of cats and fleas. 

Let "n" be the number of cats, and "2n" be the number of fleas for each cat. Therefore, the total number of fleas is 2n * n = 2n^2. 

When two cats are removed, we are left with (n-2) cats. Each of these cats now has 2n-3 fleas. Therefore, the total number of fleas remaining is (n-2)(2n-3). 

According to the problem, this is equal to half the original number of fleas: 

(n-2)(2n-3) = (1/2)(2n^2) 

Simplifying this equation gives: 

2n^2 - 7n + 6 = n^2 

Subtracting n^2 from both sides gives: 

n^2 - 7n + 6 = 0 

Factoring this quadratic equation gives: 

(n-6)(n-1) = 0 

Therefore, n = 6 or n = 1. 

However, if n = 1, then there is only one cat, which contradicts the assumption that we removed two cats. Therefore, the only solution is n = 6. 

So there are 6 cats, and each cat has 2n = 12 fleas. Intotal, there are 2n^2 = 72 fleas. 

If we remove two cats and three fleas from each remaining cat, we are left with (6-2) = 4 cats, each with (2*6-3) = 9 fleas. Therefore, the total number of fleas remaining is 4*9 = 36. 

And indeed, 36 is half of the original number of fleas, which was 72. So n = 6 is the correct solution.

Uh, but when you were multiplying the (n-2)(2n-3), wouldn't it multiply/add to -7n?

The original number of fleas is 2n*n=2n^2. After two cats are removed, there are n-2 cats left. The number of fleas remaining is (n-2)(2n-3)=2n^2-8n+6. We are told that this is half the original number of fleas, so 2n^2-8n+6=2n^2/2=n^2. Solving for n, we get n=3. Therefore, the value of n is 3​.

Hi Eggrick2011, thanks for that well explained answer.

Unfortunately you made a careless error.  Could you fix it please?

draw a graph and find the x value of point d that makes the area of xyd 20

simplify 3^2 first to get 9

9 times 4.75 is 36 + 9 * 3/4 or 27/4 

so 9 times 4.75 is 42 3/4 or 171/4

then you multiply by pi.

the answer is 171/4\(\pi \)

Since you want the least average, then you want the most amount of small numbers

There has to be a 5.5 median so the list would have to  have one 5 and one 6.

so the list would be 1,2,3,4,5,6,7,8,9,10 since there cannot be reapeats

1+2+3+4+5+6+7+8+9+10 is 11* 5 since 1+10 is 11 2+9 is 11...

so the average is 55/10 or 5.5

answer at https://web2.0calc.com/questions/counting_17460

Whoever typed that first answer was wrong. 

The answer is 30 degrees because 18-(-12) = 18+12, which is 30. We are taking the change in temperature; we're not adding both of them.

P.S. (Also can you not write the same question 3 times? Thanks!)

there is 6 ways it could happen: r, b, w   r, w, b  b, r,w  and so on blah blah blah

and there are 6*6*6 total possibilities so 

6/6*6*6 is 1/36

-12 to 18 is 18-(-12) which is equal to 18+12 which is 30. Double negative become positive

I'm not sure of the options for that question, but I can provide the simplest form.

3(2x-8)-11x

First, let's follow PEMDAS and distribute within the inside of the parenthesis. 3(2x-8) = (3 * 2x) - (3 *[-8]) = 6x-24. 

Then, let's take like terms and subtract -11+6x = -5x.

Therefore, putting them together, we get -5x-24.

Thanks! 

if you mean simplify then

first distribute the 3 in 3(2x-8) which is equal to 6x-24.

then you substract 11x from 6x-24 to get -5x-24

I think the answer is 12/19

To get no solutions the variable side must cancel out.

Since the last equation only has variables x and z, we have to cancel the y so

Multiply x+y+3z=10 by 8 to get 8x+8y+24z=80

substract the second equation to get 12x+19z=63

then we have to cancel the z

multiply the last equation by 19 to get 19xz+19z=57

 (12x+19z=63)-(19xk+19z=57) to get 12x-19xk=6

the left side of the equation must equal zero, so 12x=19xk

19k=12

divide by 19

k=12/19

-12-(-3) is -12+3 or -8. But the difference is positive so 8.

The answer is 15.