Digital SATMath: Problem-Solving and Data AnalysisMedium
A city's population increased from 180,000 to 198,000 in one year. What was the percentage increase in the population?
- A9%
- B10%
- C12%
- D8%
Show answer & explanationAnswer & explanation
Correct answer: B. 10%
The increase in population is 198,000 - 180,000 = 18,000. To find the percentage increase, divide the increase by the original population and multiply by 100: (18,000 / 180,000) * 100% = 0.10 * 100% = 10%.
Why the other options are wrong
- A. Incorrect. This would be the percentage if the increase was 16,200.
- C. Incorrect. This would be the percentage if the increase was 21,600.
- D. Incorrect. This would be the percentage if the increase was 14,400.
Percentage Change
Percentage change measures the relative difference between an old value and a new value, expressed as a percentage of the old value.
- Formula: ((New Value - Old Value) / Old Value) * 100%
- Positive result indicates a percentage increase
- Negative result indicates a percentage decrease
Memory trick: New Minus Old, Over Old, Times Hundred.