Hi parmensm. There is also a percent-change formula. Changing from an Old value to a New value, we have:
\(\displaystyle \frac{\text{New} \;–\; \text{Old}}{\text{Old}} = \text{Percent Change}\)
A positive result represents a percent increase, and a negative result represents a percent decrease.
EG: For the last two years, I've paid $2.99 per box of my favorite soup crackers. The price changed to $4.10 a month ago.
\(\displaystyle \frac{4.10 \;–\; 2.99}{2.99} = 0.3712\)
That result is the decimal form of the percent change (rounded off). To express the result using a percent sign, we multiply by 100%.
0.3712 × 100% = 37.12%
Despite inflation running between 8% and 9% in the United States over the past two months, the percent increase in my cracker cost is more than four times as high.
?
[imath]\;[/imath]