Chapter 7: Ratios, Proportions, and Percentages 97Let’s start with an example of a percent increase.
Allison invests $800 in a stock she researched. After a year, her investment is worth $920. What is
the percent increase in the value of her investment?
Original: $800
Increase: $920 – $800 = $120
The value of her investment increased by approximately 15%.
Here’s another example. This time it’s a decrease, but your method is the same.
Melissa buys $200 worth of collectibles at a f lea market and tucks them away, hoping they will
increase in value. Unfortunately, when she tries to sell them, she finds they are only worth $175.
What is the percent decrease in the value of her investment?
Original: $200
Decrease: $200 – $175 = $25
Her investment decreased approximately 12.5%.
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