example 1 finding a percent of decrease during the summer, a bear’s heart rate is about 60 beats...
TRANSCRIPT
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 – 860
=5260
= 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 – 825825
= 82545
5.45%
Write amount of increase and divide by original amount.
Subtract.
Write fraction as a decimal.
Write decimal as a percent.
= 0.0545__
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 16,189 75,273+ =
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 = 50New amt = 36
28%=
The change is a decrease since the new amount is less than the original amount
ANSWER
2. Original amt = 10New amt = 29.5
195%=
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 = 90New amt = 110
22%=
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.