# Basic Problem of something more?

• Oct 17th 2011, 12:53 PM
Rastanking
Basic Problem of something more?
Hi everyone,

I wonder if someone could have a look at this for me please, I know it's basic but I can't seem to get the answer they have in the book.

Find t in the equation

175.51 + (-44558) + 20.556(t - 25) = 0

My way is as follows

-44383 + 20.556(t - 25) = 0

-44383 + 20.556t = 0 + 25

(25 + 44383) / 20.556 = t

This gives me 2160.34, the answer quoted in the book is 2356.16

Which one is correct and if it's the latter what am I doing wrong?

• Oct 17th 2011, 01:18 PM
Quacky
Re: Basic Problem of something more?
1) You forgot the $\displaystyle .51$ between steps $\displaystyle 0$ and $\displaystyle 1$
2)You've expanded $\displaystyle 20.556(t-25)$ incorrectly. This means:
$\displaystyle 20.556(t)-20.556(25)$

How I'd start: multiply everything by 1000:

$\displaystyle 175510-44558000+20556(t-25)=0$

Rearrange:

$\displaystyle 20556(t-25)=44558000-175510$

Divide both sides by 20556:

$\displaystyle t-25=\frac{44558000-175510}{20556}$

$\displaystyle t=25+\frac{44558000-175510}{20556}$

However this does not give the answer you suggested. Are you sure you've written the question correctly?