I have another stumper from my Accounting class:

A company had net income of $561,600 in 2010 and it experienced a 17% increase in net income over 2009. What was its 2009 net income?

I can write down the formula, but I still do not understand the steps to solve it:

17% = ($561,600 – X) / X

How do I get X on one side... since it's already only on one side?

That's what I get for taking Accounting before Business Math... maybe I would have learned this already.

You guys have been so helpful. It takes about 3 days to get an answer from my online professor... so I am really getting behind in my work.:(

Look here: .17=(561,600-x)/x - Wolfram|Alpha (http://www.wolframalpha.com/input/?i=.17%3D%28561%2C600-x%29%2Fx)

Hit the equal sign at the end of the input.

Look at the second alternate form of the equation which is easy and is what you have to get and multiply everything by x.

This:
($561,600 – X) / X

can be written as

$561,600/X - X/X

which simplifies to $561,600/X -1

So you have:

0.17 = $561,600/x -1

and you only have one X to solve for.

Business math probably wouldn't have helped much. That's algebra. Were you given that equation, or did you come up with that on your own? And are you required to use it? (If you are, ignore me.)

Because there's a non-algebraic way of looking at it. (Same math involved, but a different way of thinking about it.)

If 2010 is a 17% increase over 2009, then 2010 is 117%. This is an "after an increase" problem. If you have an increase, you add it to 100% and that gives the amount after the increase.

Then you can use basic "base, rate, part" stuff to solve it. The 100% (2009 net income) is the base. The rate is the 117%. The part (after increase) is 2010 net income.

Base = Part/Rate

If you get used to doing these, any time you have an increased amount, add the percent to 100%. Then take the increased number you know and divide by the percent to get back to the original number. I do that without even thinking about the math involved at all cause I've had to do it a gazillion times.