Real Life Exponential Functions

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

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

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(1.015)^t models the population of elephants in a wildlife refuge after t years since 1975.
What does the value 1.015 represent?

• The number of elephants was 1,015 in 1975.

• The number of elephants increases by 1.5% each year.

• The number of elephants increases by 101.5% each year.

• The number of elephants is multiplied by 1.015 each year.

Which function best models the number of game consoles sold in millions x years since 2009?

• g(x)=0.6(25.5)^x

• g(X)=25.5(0.6)^x

• g(x)=6.12(25.5)^x

• g(x)=25.5(6.12)^x

If a quantity doubles every 3 days, which function models this situation?

Which of the following exponential functions best models the cooling of the hot chocolate?

• $2677.5

• $19361.1

• $3254.52

• $6231

• 19

• 17

• 38427

• 38425

• 38

• $2677.5

• $19361.1

• $3254.52

• $6231