GED Mathematical Reasoning TestQuantitative Problem Solving with Rational NumbersMedium
A city's population increased from 120,000 to 129,600 in one year. What was the percentage increase in the population?
- A9.6%
- B8%
- C6%
- D7.5%
Show answer & explanationAnswer & explanation
Correct answer: B. 8%
First, find the increase: 129,600 - 120,000 = 9,600. Then, divide the increase by the original population and multiply by 100 to get the percentage: (9,600 / 120,000) * 100 = 0.08 * 100 = 8%.
Why the other options are wrong
- A. This is incorrect; it might be the difference divided by the new population.
- C. This is incorrect; it might be a miscalculation of the increase.
- D. This is incorrect; it might be a miscalculation of the base or increase.
Percentage Change
Percentage change (increase or decrease) is calculated by finding the difference between the new and original values, dividing by the original value, and then multiplying by 100.
- Percentage Change = ((New Value - Original Value) / Original Value) * 100.
- Original value is always the denominator.
- A positive result is an increase, a negative result is a decrease.
Memory trick: New minus old, divide by old, then times 100, that's the story told.