Exponential Word Problems

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

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

• y=5000(0.7)^x

• y=30(5000)^x

• y=5000(1.3)^x

• y=5000x^x

You have inherited land that was purchased for $30,000 in 1960. The value of the land increased by approximately 5% per year. What is the approximate value of the land in the year 2011?

• $361,223.09

• $15,000.00

• $31,500.29

• $280,500.86

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

• y = 15(35)^x

• y = 15(0.35)^x

• y = 15(1.35)^x

• y = 35(1.15)^x

Is this exponential growth or decay?

• Growth, because of 7

• Growth because of 1.2

• Decay, because of 1.2

• Decay because of 7

The value of a car is $15,000 and depreciates at a rate of 8% per year. What is the exponential equation?

• y=8(15,000)^x

• y=15,000(0.92)^x

• y=15,000(1.08)^x

• y=15,000(0.08)^x

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

• y=5000(0.7)^x

• y=5000(1.3)^x

• y=30(5000)^x

• y=5000x^x

The population of Boringtown decreased annually by 1.8% between the year 2015-2018. In 2015, there were approximately 200,000 people living in Boringtown. Which function models the city's population since 2015?

• f(x) = 200,000(1 + 0.018)³

• f(x) = 200,000(1 - 0.18)³

• f(x) = 200,000(1 + 0.18)³

• f(x) = 200,000(1 - 0.018)³

Rapunzel's hair grew 16% each week she was in the tower. If her hair was 20 inches long when she was placed in the tower, what is a model for the growth of Rapunzel's hair?

If Jack's Bean stalk grew 75% every hour and the bean stalk was 2 foot when he started watching it grow, what is a model for the growth of the bean stalk?