Percent word problems

1st problem:

Let's consider an easier problem and then we'll substitute the correct numbers, okay? Let's say you have $1,000 in sales in the first year and the increase is 20%, or $200. So the second year's sales are $1,200. How do you get from $1,000 to $1,200? Multiply the first year's sales times 1.2 (e. g. that's the first year's total plus the percentage increase. You need the one in there, to the left of the decimal; otherwise, you end up with a lower amount for second-year sales, and that's wrong).

2nd problem:

55-45 means 10 sets remain unsold. What's the % of 10 out of 55? That's what you want to be looking for.

Or in a much simpler version:

A percent is just an easier way to say "this number out of 100." You want to turn the percent into a decimal, so divide the percent by 100.
20.0% / 100 = .20 (Just move the decimal point to the left two places)

To find the percent of a number, you multiply the decimal of that percent by the number.
.20 x $1,000 = $200

Finally, you add the percent of that number ($200) to the original number ($1000).
$200 + $1000 = $1,200

The increase was $200 while the total sales were $1,200.