Help with a maths problem

2007-12-09 20:13:22

#26

seb--morin: Im high; +152|7077|Montréal, Québec

Okay i got an other one tonight....

a floor mat is 3x4 meters and it is placed in a rectangular room. It's placed in the room to make all side of the mat at a constant distance of the walls.Find the dimensions of the room's floor, knowing that the area of the floor is the double of the floor-mat.

*sorry for the creepy English... I'm from Québec.... accents FTW éêûçèàùùùééùï !!!!! **

Last edited by 0seb--morin0 (2007-12-09 20:22:08)

2007-12-09 20:22:13

#27

seb--morin: Im high; +152|7077|Montréal, Québec

anyone can help ! ?

2007-12-09 20:26:21

#28

imortal: Member; +240|7102|Austin, TX

0seb--morin0 wrote:
Okay i got an other one tonight....

a floor mat is 3x4 meters and it is placed in a rectangular room. It's placed in the room to make all side of the mat at a constant distance of the walls.Find the dimensions of the room's floor, knowing that the area of the floor is the double of the floor-mat.

*sorry for the creepy English... I'm from Québec.... accents FTW éêûçèàùùùééùï !!!!! **

anyone can help ! ?

3 * 4 = 12
(3+x) * (4+x)= 24

sorry, all I can help for now.

2007-12-09 20:29:22

#29

S.Lythberg: Mastermind; +429|6884|Chicago, IL

0seb--morin0 wrote:
Okay i got an other one tonight....

a floor mat is 3x4 meters and it is placed in a rectangular room. It's placed in the room to make all side of the mat at a constant distance of the walls.Find the dimensions of the room's floor, knowing that the area of the floor is the double of the floor-mat.

*sorry for the creepy English... I'm from Québec.... accents FTW éêûçèàùùùééùï !!!!! **

that ones really easy, I think you can manage...

but if you cant:

area of the mat=12 meters
area of floor = 12x2= 24 meters
24= xy

x-3=y-4

x=y-1

combine:

24=y(y-1)

solve the quadratic:

y^2-y-24=0

y=5.4244 meters

x=4.4244 meters

Algebra FTW...

2007-12-09 20:30:17

#30

Scorpion0x17: can detect anyone's visible post count...; +691|7203|Cambridge (UK)

cba to work it out for you, but, from what I think the question is asking, you need to start with:

(2n+3)(2n+4)=24

then, re-arrange to give an equation in the form n=...

then, 2n+3 is the width, and 2n+4 is the length...

I think...

Or there's probably an easier way to do it...

But it's a little late to be stressing my poor little brain with maths problems...

2007-12-09 20:30:39

#31

imortal: Member; +240|7102|Austin, TX

3+x = 24 / (4+x)
3+x=24/4 + 24/x
3+x= 6+ 24/x
x= 3 + 24/x
x-24/x=3

REALLY not sure about this... been a very long time doing this kind of work.

***EDIT scorpion is right about it needing to be a 2n instead of x; sorry.

Last edited by imortal (2007-12-09 20:32:04)

2007-12-09 20:31:51

#32

nukchebi0: Пушкин, наше всё; +387|6761|New Haven, CT

Area of room = 24 square meters.

Factors of 24:

3, 8
4, 6
5, 4.8

These all don't work.

However, we know the constant distance is there.

Thus, we can say the dimensions are (3+2c)(4+2c)=24

FOILing: 4c^2+14c+12=24

Set it equal to zero. 4c^2+14c -12=0

Solve for c. You should know how to do this, so I'll leave it at that. If you get two answers, remember that anything under zero isn't an option.

2007-12-09 20:33:37

#33

DesertFox-: The very model of a modern major general; +796|7122|United States of America

0seb--morin0 wrote:
Okay i got an other one tonight....

a floor mat is 3x4 meters and it is placed in a rectangular room. It's placed in the room to make all side of the mat at a constant distance of the walls.Find the dimensions of the room's floor, knowing that the area of the floor is the double of the floor-mat.

*sorry for the creepy English... I'm from Québec.... accents FTW éêûçèàùùùééùï !!!!! **

Well you figure out that the area of the mat is 12 m and thus the area of the room is 24 m. Now all you have to do is make it so that (x + 3)(x +4) = 24 since x is the constant distance from the edge.

x² + 7x - 12 = 0.

Now quadratic it:
-7±√(49-4(-12))
2

And since we want a positve value [-7+√(97)]/2 should be your answer, or so I would guess.

2007-12-09 20:35:44

#34

S.Lythberg: Mastermind; +429|6884|Chicago, IL

you guys can stop now, the room is 5.4244 x 4.4244 meters.

edit: He's not even online anyway...

Last edited by S.Lythberg (2007-12-09 20:36:28)

2007-12-09 20:36:33

#35

DesertFox-: The very model of a modern major general; +796|7122|United States of America

S.Lythberg wrote:
you guys can stop now, the room is 5.4244 x 4.4244 meters.

And thus the distance that is constant is 1.4244 m.

2007-12-09 20:38:50

#36

S.Lythberg: Mastermind; +429|6884|Chicago, IL

DesertFox- wrote:
S.Lythberg wrote:
you guys can stop now, the room is 5.4244 x 4.4244 meters.
And thus the distance that is constant is 1.4244 m.

yep, the BF2s squad saves the day yet again!

2007-12-09 20:46:49

#37

nukchebi0: Пушкин, наше всё; +387|6761|New Haven, CT

Except the constant isn't the answer, the dimensions are.

2007-12-10 18:02:51

#38

seb--morin: Im high; +152|7077|Montréal, Québec

nukchebi0 wrote:
Area of room = 24 square meters.

Factors of 24:

3, 8
4, 6
5, 4.8

These all don't work.

However, we know the constant distance is there.

Thus, we can say the dimensions are (3+2c)(4+2c)=24

FOILing: 4c^2+14c+12=24

Set it equal to zero. 4c^2+14c -12=0

Solve for c. You should know how to do this, so I'll leave it at that. If you get two answers, remember that anything under zero isn't an option.

To solve C, why i just don't send the +12 with the 24 instead of doing [ 4c^2+14c -12=0] then solving C and getting negative value...

2007-12-10 18:04:04

#39

nukchebi0: Пушкин, наше всё; +387|6761|New Haven, CT

How are you going to use the quadratic formula?

S.Lythberg did it best, though. You should use his example.

Last edited by nukchebi0 (2007-12-10 18:04:55)

2007-12-10 18:05:19

#40

seb--morin: Im high; +152|7077|Montréal, Québec

I dunno what you mean there, i though i only had to find the value of C. A positive real number.

Okay i'll go with algebra.... Thks for everybody that took time to write an answer. It feel good to have a community like Bf2s' to help me out.

Last edited by 0seb--morin0 (2007-12-10 18:07:10)

2007-12-10 18:06:36

#41

nukchebi0: Пушкин, наше всё; +387|6761|New Haven, CT

0seb--morin0 wrote:
I dunno what you mean there, i though i only had to find the value of C. A positive real number.

You need to use the quadratic formula to find the values of c.

2007-12-10 18:08:34

#42

S.Lythberg: Mastermind; +429|6884|Chicago, IL

0seb--morin0 wrote:
I dunno what you mean there, i though i only had to find the value of C. A positive real number.

Okay i'll go with algebra.... Thks for everybody that took time to write an answer. It feel good to have a community like Bf2s' to help me out.

yes, but c is raised to the power of 2, meaning that there are two possible answers, and you have to solve a quadratic equation to make sure that they both arent possible answers.

2007-12-10 18:12:37

#43

nukchebi0: Пушкин, наше всё; +387|6761|New Haven, CT

You're welcome.

BF2S Forums Help with a maths problem

0seb--morin0 wrote:

0seb--morin0 wrote:

0seb--morin0 wrote:

S.Lythberg wrote:

DesertFox- wrote:

S.Lythberg wrote:

nukchebi0 wrote:

0seb--morin0 wrote:

0seb--morin0 wrote:

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