[GennadiyRom]

Hi guys! I know alot of you guys/gals are real good with this stuff, this problem has been bugging me for a while...

The dimensions of a rectangular box are consecutive integers. If the box has a volume of 13,800 cubic centimeters, what are its dimensions? --
the answers are 23,24 25 but HOW do i get that answer? [stupid]

full-explanation appreciated :-)

Thanks in adv![help][help]

[BorBitExatini]

x*(x + 1)(x+2) = 13800

x^3 + 3x^2 + 2x = 13800

umm.... well.. basically we get x^3 + 3x^2 + 2x - 13800 = 0, and then we find the intercepts...

I don't remember how to do it... have to look it up sorry...

[MichaelfromSpace]

easy:

let the middle term be n, then the other two terms are (n-1) and (n+1), since they are consecutive:

volume = w * h* d //if you don't know this by now well...
13800 = (n-1)*n*(n+1) // substitute in unknowns
13800=(n^2-n) * (n+1) // expanding, step 1
13800=n^3+n^2-n^2-n //fully expanded
138000=n^3-n
n=24

hence the 3 terms are 24, 24+1 and 24-1

[2 minutes too late]...

[GennadiyRom]

thanks!! [thumbup][thumbup]

[MichaelfromSpace]

thanks!! [thumbup][thumbup]

should i be feeling better now? i just bombed a first year uni chem mid-term?! [cursing]

[mv37afnr]

should i be feeling better now? i just bombed a first year uni chem mid-term?! [cursing]

Guess you should have taken precalc instead.

[BorBitExatini]

I can't believe I can't remember how to completely solve these types of problems... maybe my mind is melting due to my test in Linear Algebra and Differential Equations tomorrow.... CURSE YOU ADVANCED MATHEMATICS!!