Exponential and Compound Interest Practice

A city has a population of 21,517 based on a census taken in 1998. If the population is expected to grow by 11% annually, what will the population be in the year 2030?

• 606,900
• 517
• 492,573
• None of these

James deposits $200 in a savings account with an annual interest rate of 4%. About how many years will it take James to earn $160 in interest?

• 10
• 12
• 15
• 160

Your 2 year investment of $5,300 earns 2.9% and is compounded annually.  What will your total return be?

• $5,304.46
• $5,611.86
• $5,613.28
• $8,819.73

Is this exponential growth or decay?

• Growth
• Decay

The population of turtles is doubling every 3 months.  If there are 400 turtles now, how many will there be in 2 years?  (Choose equation)

• y = 400(2)²
• y = 400(2)⁶
• y = 400(2)⁸
• y = 400 + 2(8)

The projected worth (in millions of dollars) of a large company is modeled by the equation y=271(1.07)^x .  The variable x represents the number of years since 1997. What should the company be worth be in 2008?

• 570.41 million
• 523.21 million
• 600.34 million
• 702.57 million

What does the a in y=a(1+r)^x  represent?

• Time
• Rate
• Slope
• Initial Amount

Since January 1980, the population of the city of Brownville has grown according to the mathematical model y=720,500(1.022)^x, where x is the number of years since January 1980. What is the percentage increase of the population annually?

• 720,500%
• 102.2%
• 2.2%
• 22%

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

The attendance at the art museum at the New Year’s opening was 250 people. The attendance has been increasing at a rate of 3% each month. How many people will attend by the end of a year?

• 356
• 265
• 5825
• 1329