Final answer:
Santos' walking time decreased from 40 minutes to 25 minutes, which is a 37.5% decrease. This indicates that he has gotten faster.
Step-by-step explanation:
To determine if the percent of change in Santos' walking time is an increase or a decrease, you need to calculate how much his time has changed from the initial time to the new time. The original time it took Santos to walk 2 miles was 40 minutes, and his new time is 25 minutes. To calculate the percent of change, you subtract the new time from the original time and then divide by the original time, finally multiplying by 100 to get a percentage.
The calculation would be: ((Original Time - New Time) / Original Time) * 100 = Percent of Change
In Santos' case: ((40 minutes - 25 minutes) / 40 minutes) * 100 = (15 minutes / 40 minutes) * 100 = 37.5%
Since the time has decreased, it means Santos is now walking faster. Therefore, the percent of change in his walking time represents a decrease.