1. ## Profit Help

I'm having a little difficulty solving growth/decay facts, I suppose this question is about that but I'm having a little difficulty understanding what it means

Question: Keller industries' profit were up $50,000$ this year over last year. This was an increase of $12.5%$

Let T represent the profit this year and L the profit from last year and write a system of equations that can be used to determine the profits?

2. ## Re: Profit Help

Originally Posted by awfulatmath
...
Question: Keller industries' profit were up $50,000$ this year over last year. This was an increase of $12.5%$

Let T represent the profit this year and L the profit from last year and write a system of equations that can be used to determine the profits?
Hello,

you only have to extract 2 equations from the text:

$\begin{array}{r}L + \frac{12.5}{100} \cdot L = T \\ L + 50,000 = T \end{array}$

Solve for L and T.

3. ## Re: Profit Help

Thanks so much, for the equations.

Now when solving is it possible to use the Elimination or Substitution method when solving? Since I can solve for both L and T variables?

4. ## Re: Profit Help

Originally Posted by awfulatmath
Thanks so much, for the equations.

Now when solving is it possible to use the Elimination or Substitution method when solving? Since I can solve for both L and T variables?
either will work. Since you have two expressions for T you might as well just set them equal and immediately eliminate T from the mix. You'd get

$L+\dfrac{12.5}{100}\cdot L = L + 50,000$

and this can be solved for $L$

$L$ can then be used to find $T$ from either equation.

5. ## Re: Profit Help

I solved for $L$ and received $.125$

Or is that completely wrong? Would I take the value for $L$ and plug into $T$?

6. ## Re: Profit Help

What do you think? 50,000 was an increase of 12.5 (% although you didn't say that) of last year's profit. Is 12.5% of .125 equal to 50,000?
You are really saying that .125L= 50000.

(Note the "0.125", NOT 12.5!)

7. ## Re: Profit Help

Originally Posted by awfulatmath
I solved for $L$ and received $.125$

Or is that completely wrong? Would I take the value for $L$ and plug into $T$?
it's wrong.

subtract $L$ from both sides and you are left with

$0.125 L = 50000$

surely you can solve it from here.

Then $T=L + 50000=$