In terms of percent change, which formula is correct?

The correct formula for calculating percent change is obtained by taking the difference between the new value and the old value, dividing that difference by the old value, and then multiplying the result by 100 to express it as a percentage. This approach allows for a clear understanding of how much change has occurred relative to the original value.

Using this formula helps to highlight the impact of the change in a standardized way, making it easier to assess whether an increase or decrease in a value is significant. In many contexts, such as finance or data analysis, being able to convey changes in terms of percentage is crucial for understanding trends and making informed decisions.

Other formulations provided do not capture the percent change in the standard way. For instance, calculating the percent change by subtracting the new value from the old value could lead to confusion as it does not maintain a consistent approach to how we interpret increases versus decreases. Similarly, using the average of the two values or dividing by the new value directly does not yield a true representation of change when measured against the original baseline.