EXAMPLE 1 Finding a Percent of Decrease During the summer, a bear’s heart rate is about 60 beats per minute, but it can drop to as low as 8 beats per minute during the winter. What is the percent of change in a bear’s heart rate from the summer rate to the winter low rate? Bears SOLUTION To find the percent of decrease, use the percent of change equation.

EXAMPLE 1 Finding a Percent of Decrease p%= 60 – 8 60 = = 0.86 _ 86.67% Write amount of decrease and divide by original amount. Subtract. Write fraction as a decimal. Write decimal as a percent. The percent of decrease is about 86.7%. ANSWER

EXAMPLE 2 Finding a Percent of Increase A school had 825 students enrolled last year. This year, 870 students are enrolled. Find the percent of increase to the nearest tenth. School Enrollment SOLUTION p%= 870 – = % Write amount of increase and divide by original amount. Subtract. Write fraction as a decimal. Write decimal as a percent. = __

EXAMPLE 2 Finding a Percent of Increase The percent of increase is about 5.5%. ANSWER

EXAMPLE 3 Using Percent of Increase From October to November one year, attendance at Everglades National Park increased about 27.4%. There were 59,084 visitors in October. To the nearest hundred, how many people visited in November? National Parks SOLUTION STEP 1 Find the increase. Increase = 27.4% of 59,084 = 0.274( 59,084) 16,189 Write 27.4 % as a decimal. Multiply.

EXAMPLE 3 Using Percent of Increase STEP 2 Add the increase to the original amount. New Amount 59,084 16,18975,273 + = ANSWER About 75,300 people visited the park in November.

GUIDED PRACTICE for Examples 1, 2 and 3 Tell whether the change is an increase or decrease. Then find the percent of change. Round to the nearest percent. 1. Original at = 50 New amt = 36 28% = The change is a decrease since the new amount is less than the original amount ANSWER

2. Original amt = 10 New amt = % = GUIDED PRACTICE for Examples 1, 2 and 3 The change is an increase since the new amount is greater than the original amount ANSWER

3. Original amt = 90 New amt = % = GUIDED PRACTICE for Examples 1, 2 and 3 The change is an increase since the new amount is greater than the original amount ANSWER

GUIDED PRACTICE for Examples 1, 2 and 3 What If? In Example 3, suppose the attendance decreased by about 11 %. Approximate, to the nearest thousand, the attendance in November 4. ANSWER About 53,000 people visited the park in November.