Math Problem: You have 2 pipes...

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EyeMWing

Banned
Jun 13, 2003
15,670
1
0
3.9A+5.9B=212
(212-5.9B)/3.9=A

3.9((212-5.9B)/3.9)+5.9B=212
All the variables cancel. Thus, B can be any number. Any whole number in your case.

Now it's just a matter of finding out which value of B will give you a whole number value of A. How the fsck would you do that? I'm honestly not sure, but I'd just brute force it.
 

Anubis

No Lifer
Aug 31, 2001
78,712
427
126
tbqhwy.com
Originally posted by: EyeMWing
3.9A+5.9B=212
(212-5.9B)/3.9=A

3.9((212-5.9B)/3.9)+5.9B=212
All the variables cancel. Thus, B can be any number. Any whole number in your case.

Now it's just a matter of finding out which value of B will give you a whole number value of A. How the fsck would you do that? I'm honestly not sure, but I'd just brute force it.

thats what i woudl have done from the start, taken 5 min max
 

ndee

Lifer
Jul 18, 2000
12,680
1
0
Originally posted by: Anubis
Originally posted by: EyeMWing
3.9A+5.9B=212
(212-5.9B)/3.9=A

3.9((212-5.9B)/3.9)+5.9B=212
All the variables cancel. Thus, B can be any number. Any whole number in your case.

Now it's just a matter of finding out which value of B will give you a whole number value of A. How the fsck would you do that? I'm honestly not sure, but I'd just brute force it.

thats what i woudl have done from the start, taken 5 min max

Yeah, ANYONE could've brute force it :roll: I wasn't asking to brute force it. I'm sure a prof will accept it in a test :roll:
 

Lord Evermore

Diamond Member
Oct 10, 1999
9,558
0
76
3.9A = 212-5.9B

5.9B = 212-3.9A
5.9B = 212-3.9(212-5.9B)
5.9B = 212-(826.8-23.01B)
5.9B = -614.8-23.01B
28.91B = -614.8
B = -21.265997924593566240055344171567

You have the wrong answers. :-D
 

pray4mojo

Diamond Member
Mar 8, 2003
3,647
0
0
Originally posted by: MercenaryForHire
Originally posted by: pray4mojo
Need 2 equations since there are two variables.

Originally posted by: ndee
OK, what's the 2nd equation smarties!

Were either of you two dumbfvcks paying any attention in high school? Jesus!

Paging Kelvrick to add a few more dumbasses to his list!

- M4H

Nope but I'm sure you did.
 

Anubis

No Lifer
Aug 31, 2001
78,712
427
126
tbqhwy.com
Originally posted by: ndee
Originally posted by: Anubis
Originally posted by: EyeMWing
3.9A+5.9B=212
(212-5.9B)/3.9=A

3.9((212-5.9B)/3.9)+5.9B=212
All the variables cancel. Thus, B can be any number. Any whole number in your case.

Now it's just a matter of finding out which value of B will give you a whole number value of A. How the fsck would you do that? I'm honestly not sure, but I'd just brute force it.

thats what i woudl have done from the start, taken 5 min max

Yeah, ANYONE could've brute force it :roll: I wasn't asking to brute force it. I'm sure a prof will accept it in a test :roll:

my profs did, if just wrote brute force down and then list the values i tried till i got the answer
 

Mermaidman

Diamond Member
Sep 4, 2003
7,987
93
91
Originally posted by: Lord Evermore
3.9A = 212-5.9B

5.9B = 212-3.9A
5.9B = 212-3.9(212-5.9B)
5.9B = 212-(826.8-23.01B)
5.9B = -614.8-23.01B
28.91B = -614.8
B = -21.265997924593566240055344171567

You have the wrong answers. :-D
LOL :D
 

ohtwell

Lifer
Jan 6, 2002
14,516
9
81
Originally posted by: Lord Evermore
3.9A = 212-5.9B

5.9B = 212-3.9A
5.9B = 212-3.9(212-5.9B)
5.9B = 212-(826.8-23.01B)
5.9B = -614.8-23.01B
28.91B = -614.8
B = -21.265997924593566240055344171567

You have the wrong answers. :-D
His answers work.


: ) Amanda
 

jagec

Lifer
Apr 30, 2004
24,442
6
81
Originally posted by: Yossarian
Originally posted by: MercenaryForHire
My god. What are you in, elementary school?

3.9A + 5.9B = 212

Solve for A and B.

- M4H

there's more to it than that, and if you weren't so concerned w/putting someone down maybe you'd see that. A and B are integers so your wonderful equation doesn't answer the question.

The only reason his equation works is that they ARE integers..if they were just real numbers, he'd need two equations.
 

esun

Platinum Member
Nov 12, 2001
2,214
0
0
3.9x + 5.9y = 212
4x + 6y = 0.1x + 0.1y + 212

0.1(x + y) must be an integer

x + y must be a multiple of 10. I suppose that helps with the guess and check method, but I still don't see a direct way to the answer personally.
 

Anubis

No Lifer
Aug 31, 2001
78,712
427
126
tbqhwy.com
Originally posted by: Kelvrick
B = 32

EDIT: I just did it using hte MSN search. :D

no you did not. all you proved is that you cant read

from the OP
I have the answers(12 A-Pipes, 28 B-Pipes)
 

EyeMWing

Banned
Jun 13, 2003
15,670
1
0
Originally posted by: Lord Evermore
3.9A+5.9B=212
(212-5.9B)/3.9=A

3.9((212-5.9B)/3.9)+5.9B=212

Uhm...all that comes out to is 212=212. :) What's the point of even doing that?

To prove that A and B can be anything. Just in case.

Also, this is a common SAT-type problem - there is nothing in arithmetic=>Calc I that can be used to solve this handily.
 

ndee

Lifer
Jul 18, 2000
12,680
1
0
Originally posted by: Anubis
Originally posted by: Kelvrick
B = 32

EDIT: I just did it using hte MSN search. :D

no you did not. all you proved is that you cant read

from the OP
I have the answers(12 A-Pipes, 28 B-Pipes)

Explain it without Brute Force. I have the answer here but I can't follow/understand it.
 

Kelvrick

Lifer
Feb 14, 2001
18,422
5
81
Originally posted by: Anubis
Originally posted by: Kelvrick
B = 32

EDIT: I just did it using hte MSN search. :D

no you did not. all you proved is that you cant read

from the OP
I have the answers(12 A-Pipes, 28 B-Pipes)

It seems he edited his post before I ever entered the thread. I see no mention of 12 or 28 anywhere in the thread aside from your post.

EDIT: Arggh,t hey're in the original post. Fine! I just woke up, ok?!
 

Anubis

No Lifer
Aug 31, 2001
78,712
427
126
tbqhwy.com
Originally posted by: Kelvrick
Originally posted by: Anubis
Originally posted by: Kelvrick
B = 32

EDIT: I just did it using hte MSN search. :D

no you did not. all you proved is that you cant read

from the OP
I have the answers(12 A-Pipes, 28 B-Pipes)

It seems he edited his post before I ever entered the thread. I see no mention of 12 or 28 anywhere in the thread aside from your post.

look at the first post dude
 
Jan 31, 2002
40,819
2
0
Oi.

I have one word for you all. The BS-callers, those insulting my intelligence, and those trying to solve it via conventional algebra. Just one word.

GRAPH.

Thank you.

- M4H
 

JW310

Golden Member
Oct 30, 1999
1,582
0
0
Originally posted by: Kelvrick
Originally posted by: Anubis
Originally posted by: Kelvrick
B = 32

EDIT: I just did it using hte MSN search. :D

no you did not. all you proved is that you cant read

from the OP
I have the answers(12 A-Pipes, 28 B-Pipes)

It seems he edited his post before I ever entered the thread. I see no mention of 12 or 28 anywhere in the thread aside from your post.

Umm, look a little harder at the OP. I've even quoted it below for you. This is the OP as of the time I'm writing this reply (bold added by me).

Originally posted by: ndee
Pipe A: 3.9meter
Pipe B: 5.9meter

How many of each do you need to make a 212meter long pipe? You cannot cut them, meaning you can only use whole pipes. I have the answers(12 A-Pipes, 28 B-Pipes) but I don't understand the way. Can maybe someone explain it step by step?

Would be great, thanks in advance!


JW
 

ohtwell

Lifer
Jan 6, 2002
14,516
9
81
Originally posted by: MercenaryForHire
Oi.

I have one word for you all. The BS-callers, those insulting my intelligence, and those trying to solve it via conventional algebra. Just one word.

GRAPH.

Thank you.

- M4H
Why not just do it, and show everyone that you know what you are doing. You keep calling people idiots because they don't know how to do it, yet you have posted no proof that you do.


: ) Amanda
 

Lord Evermore

Diamond Member
Oct 10, 1999
9,558
0
76
I'm actually trying.

3.9A + 5.9B = 212

divide by 3.9A

1+5.9B/3.9A = 212/3.9A

subtract from both sides

1=212/3.9A-5.9B/3.9A

reduce the equation with like denominators

1=(212-5.9B)/3.9A

And that's as far as I get.

Of course that's a long way to go to get back to nothing more than:

3.9A = 212-5.9B

 

Farvacola

Senior member
Jul 14, 2004
753
0
0
I've been trying, but I believe my math in that area is rusty, so I keep making weird little errors. Arggghe I shant stop till i solve it!