Percentages — Increase, Decrease, and Multi-Step

SAT Math · Axiom Academy

Percentages: Increase, Decrease & Multi-Step Master percentage calculations and compound percentage problems A percentage is a ratio out of 100. Understanding how to find percentages is fundamental to SAT problems. Example 1: Finding a Percentage of a Number Example 2: Finding What Percent One Number Is of Another Percentage Increase & Decrease These formulas show how much something has changed from its original value. Example 3: Percentage Increase A jacket originally costs 80 and now costs 100. What is the percent increase? Example 4: Percentage Decrease A stock was worth 50 and is now worth 35. What is the percent decrease? Computing Final Value with Percent Change You can also find the new value after a percentage change using multipliers. Example 5: Computing Final Value A store increases all prices by 15%. If a shirt costs 40, what's the new price? Compound Percentages & Multi-Step Problems When percentage changes happen sequentially, you must apply each change to the result of the previous one. Example 6: Markup Then Discount A store buys a jacket for 40. They mark it up 50%, then offer a 20% discount. What's the final price? Final price is 48 (not 44, which would be wrong!) Example 7: Finding Net Percent Change If a price increases 25% then decreases 20%, what's the overall percent change? Overall, the price returns to its original value! Common SAT Percentage Scenarios Sales & Discounts: Original price reduced by a percentage

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