Percent Change and Error

Percent of Change

Definitions

• Percent of Change - the percent by which a number increases or decreases.

• Percent Decrease - a percent change describing a decrease in a quantity.

• Percent Increase- The percent change describing an increase in a quantity.

Multiple Choice

What is the percent of change? 55 mph to 70 mph

• 27% increase

• 27% decrease

• 21% increase

• 21% decrease

How did you do that?

Multiple Choice

What is the percent of change? 92 lb to 200 lb

• 54% increase

• 54% decrease

• 117% increase

• 117% decrease

How did you do that?

Multiple Choice

What is the percent of change? 5 ft to 5 ½ ft

• 10% increase

• 10% decrease

• 9% increase

• 9% decrease

Multiple Choice

What is the percent of change? 70 mph to 55 mph

• 21% decrease

• 21% increase

• 27% increase

• 27% decrease

Multiple Choice

What is the percen of change? 18.7 kg to 4.5 kg

• 76% increase

• 76% decrease

• 3% increase

• 3% decrease

Multiple Choice

What is the percent of change? 4.72 million to 3.15 million

• 33% increase

• 33% decrease

• 50% increase

• 50% decrease

Calculating Percent Error

Multiple Select

Which words also mean "estimate"? (check all that apply)

• guess

• exact

• approximate

• close to

Multiple Select

Which words mean ACTUAL? (Check all that apply)

• correct

• exact

• estimate

• precise

Multiple Choice

Mr. Boone estimates that it will take him 48 minutes to run 8 miles. It actually takes him 60 minutes. What was his percent error?

• 20%

• 12%

• 25%

• 8%

Multiple Choice

Ms. Meckley estimated 70 students would try out for the Cross Country team. This year, only 63 students tried out. What was her percent error?

• 11%

• 50%

• 12%

• 1%

Multiple Choice

An archaeologist estimated that a fossil was 520 years old. It was actually 500 years old. What was the percent error?

• 4%
• 20%
• 3.8%
• none of these

Multiple Choice

Find the percent error. Round to the nearest tenth of a percent.

Actual speed: 38 mph

Estimated speed: 35 mph

• 8.1%

• 0.79%

• 7.9%

• 6.8%