Percent Change and Percent Error

Front

What is percent change?

Back

Percent change is a way to express a change in a quantity as a percentage of the original amount. It is calculated using the formula: ((New Value - Old Value) / Old Value) x 100.

Front

How do you calculate the final price after a discount?

Back

To calculate the final price after a discount, subtract the discount amount from the original price. The discount amount can be found by multiplying the original price by the discount percentage.

Front

What is the formula for calculating percent error?

Back

Percent error is calculated using the formula: (|Estimated Value - Actual Value| / Actual Value) x 100.

Front

If a shirt costs $50 and is on sale for 20% off, what is the discount amount?

Back

The discount amount is $10. (20% of $50 = 0.20 x 50 = $10).

Front

What is the final price of an item that costs $80 with a 15% discount?

Back

The final price is $68. (Discount = $12; Final Price = $80 - $12).

Front

What does a percent error of 0% indicate?

Back

A percent error of 0% indicates that the estimated value is exactly equal to the actual value.

Front

How do you find the percent change when the new value is less than the old value?

Back

When the new value is less than the old value, the percent change will be negative, indicating a decrease. Use the formula: ((New Value - Old Value) / Old Value) x 100.

Front

If the estimated attendance for an event is 10,000 but only 8,000 attend, what is the percent error?

Back

The percent error is 20%. (|10,000 - 8,000| / 10,000) x 100 = 20%.

Front

What is a 10% discount on an item that costs $200?

Back

A 10% discount on an item that costs $200 is $20. (10% of $200 = 0.10 x 200 = $20).

Front

If a student estimates their test score to be 85 but actually scores 90, what is their percent error?

Back

The percent error is 5.56%. (|85 - 90| / 90) x 100 = 5.56%.