Percent Change Functions

A shoe sales associate earned $300 in August. In September she earned 8% more than she did in August. How much did she earn in September?

• $308

• $324

• $200

• $380

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x

• y = 15(1.35)^x

• y = 15(0.35)^x

• y = 35(1.15)^x

The expression 12(1.02)^t models the population of elephants in a wildlife refuge after t years since 1975.

What does the value 1.02 represent?

• The number of elephants was 102 in 1975.

• The number of elephants increases by 2% each year.

• The number of elephants increases by 102% each year.

• Two extra elephants join the population each year

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(1 - 0.30)^x

• y=30(5000)^x

• y=5000(1 + 0.30)^x

• y=5000x^x

When finding percent change you must first (a)   ​ the new number from the ​ (b)   ​ number to find the amount of change.

• subtract

• original

• add

• percent

Drag and drop the correct labels for this Percent change model.

e

f

d

percent

100

original

change

50

New Amount

What is the percent change when a quantity increases from 100 to 150?

• 25%

• 50%

• 75%

• 100%

Calculate the percent change from 50 to 75.

• 25%

• 50%

• 75%

• 100%

The original value of a painting is $1400, and the value increases by 9% each year. Write a function to model this situation.

• y=1400(1.09)^x

• y=1.09(1400)^x

• y=1400(.91)^x

• y=1.09^x

A population of fish starts at 8,000 and decreases by 6% per year. What is the population of fish after 10 years?

• 14327

• 4309

• 839

• 7680