Gh0sty15

Ah thanks CPhill. You've been saving me for the past few questions. I really appreciate it. 

Just a quick follow up. Can you explain why it can't be option B?

Oh. But isn't "abcd" one combination as well in a permutation? There isn't another "abcd"

Yeah. But I wanted to know how to find out if this situation was a permutation or combination (without knowing the answer)

When there are 4 out of 8 teams that are going to fill out the top 4, is it a permutation or combination? And why? 

Does top 4 mean there is an order? Because that would mean it would be a permutation.

Or does top 4 means any random team can enter? Because that would mean it would be a combination (I think...)

Thanks though!

Yeah, I get it now.

Thanks, a lot CPhil.

The answer sheet I have to solve this question had many flaws, so I guess it was wrong again (it often is...)

Your explanation was great! Really thorough and detailed.

Thanks again. 

Thanks CPhill 

So sorry, but could you please explain the final part of your explanation again? I'm trying to fully grasp the concept.

This is (part of) what you said: 

"So....the excess metal  surrounding all the washers is  just

Area of the sheet  - area  occupied by the washers =

(30000  - 7500pi) cm^2   (2)

So....the total amount of excess metal available  for forming new washers  is just  the sum of   (1)  and (2)  =  [  1875 pi  +  (30000 - 7500pi) ] =  [30000 - 5625 pi ]  cm^2

So....the total number of   possible washers   that can be made with a new sheet   is just

[  Area  of metal available  ]  / [ Area  occupied by each washer ]   =

[ 30000 - 5625pi ] cm^2  / [ pi] cm^2  ≈  3924 additional washers"

I just need help on the bolded part. Especially [pi] cm^2.

Thanks again.

I got Ravenclaw...

The letter 'e' ?

Hello quilly!

Yeah, like everyone said, it's a forum where you can answer and ask questions about math.

At times, people post some stuff that are fun, but there's been like a "dead" streak for about 2 months now...

You're not forced to post something that is not related to math. In fact, you'll probably get more views and likes when you post something that is funny...

But yeah, like ElectricPalov said, for private conversations, use messaging.

You know, I've been waiting for something other than math to pop up for a very long time... so this is interesting

Don't worry, it seems like everyone here likes new members.

I'm hoping everyone will liven things up here now. Not everything needs to be math-y...

But...yeah. Don't post random stuff for no reason and continuously posting un-math-y stuff isn't really a good idea. There are people who need help with their math here.

And no, this post is not considered spam. You can post something like this occasinally and everything will be fine.

Well, let's simplify.

When there dividing numbers with the same base but with different exponents, we subtract the second exponent from the first exponent. 

(m^2/5) / (m^(-8/5))

Subtract the exponents. 2/5 - (-8/5)

That would be 2/5 + 8/5, which equals to 10/5.

10/5 is 2. So the exponent would be 2.

Our final answer would be m^2

New Year, New Start, New Answer!

First answer of the year for me.

Alright, I'll try to explain this the best I can using a keyboard. 

The equation is x^2(6x - 11)(7x - 8) = 0

So, you have to figure out what you can put in for x for the whole thing to equal 0.

Roots mean possible solutions.

Let's "divide" the equation into 3 parts. 

We know that anything multiplied by 0 is 0.

And 0 to the power of anything is still 0. 

So if you plug in 0 for x^2(6x - 11)(7x - 8) = 0, You get 0 (it would look like "0(6x-11)(7x-8)" )

So the first root is 0.

Next, let's look at the (6x - 11) part. 

Remember that anything multiplied by 0 is 0. 

So, 6x - 11 must equal to 0.

6x-11=0

6x=11

x=11/6

So another root is 11/6.

Finally, let's look at (7x-8) 

That should also equal 0, no matter what it is multiplied by.

7x-8=0

7x=8

x=8/7

The last root is 8/7

So the three roots are 0, 11/6, and 8/7.

Happy Birthday! 

(Is your Birthday the 19th or the 20th?)