Percent Change and Percent Error

Front

What is percent change?

Back

Percent change is a measure of how much a quantity has increased or decreased relative to its original value, expressed as a percentage.

Front

How do you calculate percent change?

Back

Percent Change = ((New Value - Original Value) / Original Value) x 100.

Front

What is percent error?

Back

Percent error is a measure of how inaccurate a measurement is, compared to the true value, expressed as a percentage.

Front

How do you calculate percent error?

Back

Percent Error = (|Estimated Value - Actual Value| / Actual Value) x 100.

Front

If the actual speed is 38 mph and the estimated speed is 35 mph, what is the percent error?

Back

Percent Error = (|35 - 38| / 38) x 100 = 7.9%.

Front

Alex buys a car for $45,800 and sells it for $61,830. What is the percent of change?

Back

Percent Change = ((61,830 - 45,800) / 45,800) x 100 = 35% increase.

Front

If Sam thinks a book costs $50 but it actually costs $56, what is his percent of error?

Back

Percent Error = (|50 - 56| / 56) x 100 = 10.7%.

Front

A shoe sales associate earned $300 in August and 8% more in September. How much did she earn in September?

Back

September Earnings = 300 + (0.08 x 300) = $324.

Front

If a quantity increases from 53 to 62, what is the percent of change?

Back

Percent Change = ((62 - 53) / 53) x 100 = 17.0% increase.

Front

What does a positive percent change indicate?

Back

A positive percent change indicates an increase in value.