Lesson 6-5 Percent of Change - Increase/Decrease

[Pages:7]Lesson 6-5 Percent of Change - Increase/Decrease

____%

rate of change

of _____ is _____

original number

amount of

change

____%

rate of change

of _____ is _____

original number

amount of

change

1. In 1981, there were 25 endangered and threatened species of reptiles in the U.S. In 2001, there were 20 species. By what percent did the number of these reptile

species change from 1981 to 2001?

2. The price of a hamburger at a baseball stadium was $3.25. The following year, the price of the hamburger was $4.15 By what percent did the price change?

Answers on next slide

__x__%

rate of change

of __2_5 __ is ___5__

original number

amount of

change

1. In 1981, there were 25 endangered and threatened species of reptiles in the U.S. In 2001, there were 20 species. By what percent did the number of these reptile

species change from 1981 to 2001?

This is a decrease. (to change the decimal to a percent)

change original

25 20 x 100

25

5 = 0.2 x 100 = 20% decrease 25

__x__% rate of change

of __3._25__ is __0_.9__

original

amount

number

of

change

2. The price of a hamburger at a baseball stadium was $3.25.

The following year, the price of the hamburger was $4.15 By

what percent did the price change?

This is an increase.

change original

4.15 3.25 = 0.9 0.277

3.25

3.25

0.277 x 100 = 27.7% increase

____% rate of change

of _____ is _____

original

amount

number

of

change

____% rate of change

of _____ is _____

original

amount

number

of

change

This is an increase.

change original

61 - 52 52

=

9 52

0.173

x 100 = 17.3% increase

_1_7_.3_% rate of change

of __5_2__ is __9___

original

amount

number

of

change

This is a decrease.

change original

24-18 24

=

6 24

=

0.25

x 100 = 25% decrease

_2_5__% of _2_4___ is __6___

rate

original

amount

of

number

of

change

change

Percent Error

_____% of _______ is _________

actual

amount of error

actual - the "real" amount amount of error - the difference between the prediction or estimate and the actual amount.

1. Alyssa estimates that her school auditorium has 660 seats. It actually has 750 seats. What is the percent error of her estimate?

Answer on next slide

1. Alyssa estimates that her school auditorium has 660 seats. It actually has 750 seats. What is the percent error of her estimate?

amt. of error actual

750 - 660 750

=

90 750

= 0.12 x 100

= 12% error (underestimated)

2. A company replaced a half gallon container of orange juice with a 59 ounce container. If a customer does not notice the change in size, what is the percent error to the nearest tenth?

Answer on next slide

2. A company replaced a half gallon container of orange juice with a 59 ounce container. If a customer does not notice the change in size, what is the percent error to the nearest tenth?

***Before you can solve this problem, the units must be the same.

1 gallon = 128 ounces 0.5 gallon = 64 ounces

amt. of error actual

64 - 59 64

=

5 64

= 0.078

0.078 x 100 = 7.8% (underestimated)

3. The estimate for the amount of rain in May in one part of Texas was 5.6 inches. The actual rainfall was 2.4 inches. What was the percent error of the estimate to the nearest percent?

3. The estimate for the amount of rain in May in one part of Texas was 5.6 inches. The actual rainfall was 2.4 inches. What was the percent error of the estimate to the nearest percent?

amt. of error actual

5.6 - 2.4 2.4

=

3.2 2.4

=

1.33

1.33 x 100 = 133%

(overestimated)

Answers on next slide

20% decrease

12.5% increase

30.8% decrease

20% underestimated 6.7% overestimated

13.3% overestimated

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