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Learn how to find the percent of change for a given increase or decrease. Discover how to calculate the increase or decrease given a percent of change using simple examples. Master the concept of percent of change with sample problems.
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Texas Algebra I Lesson 33: Percent of Change
Lesson Objectives: The student will be able to: • Find the percent of change for a given an increase or decrease. • Find the increase or decrease given a percent of change
Percent of Change (amount of change) Formula: (new – original) ÷ (original) Simple examples: Original price: $100 original: 20 marbles New price: $25 new: 100 marbles
Sample problems Physical therapist measure strength on a dynamometer, which uses a unit called a “foot-pound”. Suppose you increase the strength in your elbow joint from 90 ft-lbs to 125 ft-lbs. Find the percent of change in elbow strength.
Sample problems 2. In 1999 the number of days of unhealthy air quality in a U.S. city was 2. By 2006, that number had risen by 60%. Find the number of unhealthy air quality days for the given U.S. city in 2006.
Lesson Objectives: The student will be able to: • Find the percent of change for a given an increase or decrease. • Find the increase or decrease given a percent of change