Solving Exponential Word Problems

Mr. thingamajig invested an amount of money at a rate of 2.85% continuously. After 6 years, his balance was $1,779.74. How much was his original investment.

• 1550

• 1450

• 1500

• 1600

In 1985, there were 285 cell phone subscribers in the small town of Centerville. The number of subscribers increased by 75% per year after 1985. How many cell phone subscribers were in Centerville in 1994?

• OVERFLOW

• 1994

• 1000

• 43871

Bacteria can multiply at an alarming rate when each bacteria splits into two new cells, thus doubling. If we start with only one bacteria which can double every hour, how many bacteria will we have after half of a day?

• 1024

• 2048

• 8192

• 4096

More and more people are purchasing food from farmers' markets. As a consequence, a market researcher predicts that the number of farmers' markets will increase by 15% each year. If there are 6,200 farmers' markets this year, how many will there be in 10 years? (Round to the nearest whole number if necessary).

• 25,082

• 12,937

• 62,000

• 43,511

A publishing industry report predicts that magazine subscriptions will drop by 10% each year. If this prediction is correct, then how many subscribers will a magazine with 98,000 subscribers have in 10 years? (Round to the nearest whole number if necessary).

• 34,170

• 16,348

• 7690

• 76,023

Jenny has $20 in a savings account. The interest rate is 5%, compounded annually. To the nearest cent, how much interest will she earn in 2 years?

• $2.05

• $45.79

• $1.99

• $7.51

Lauren has $90 in a savings account. The interest rate is 5%, compounded annually. To the nearest cent, how much will she have in 2 years?

• $99.23

• $21.98

• $56.46

• $9.21

A cliff overlooking Oak Grove Lake is experiencing erosion, losing elevation at a rate of 5% every millennium. The cliff's current elevation is 1,200 meters. What will its elevation be in 6 millennia? (Round to the nearest whole number if necessary).

• 882

• 465

• 349

• 975

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?

• $344,022

• $31,500

• $15,000

• $28,500

You drink a beverage with 120 mg of caffeine. Each hour, the caffeine in your system decreases by about 12%. How long until you have 10mg of caffeine?

• 19 to 20 hours

• 10 to 20 hours

• 15 to 16 hours

• 5 to 6 hours