Growth or Decay?
Population
$$
Compounding Interest
100

You purchase a vehicle for $25,400 in 2015.  This brand of vehicle typically depreciates at a rate of 3.2% each year.  What is the value of the vehicle now?

Write the equation.

Growth

y=25,400(1-0.032)^9


100

Shepherd's population has been growing at a rate of 0.2% each year.  If the population was 4,230 in 1990, what is the projected population for 2030?

4,582 people

100

You purchase a vehicle for $25,400 in 2015.  This brand of vehicle typically depreciates at a rate of 3.2% each year.  What is the value of the vehicle now?

$18,282.87

100

You put $5,000 into an account that gains 1.4% interest, compounded quarterly.  How much will you have after 12 years?

$5,912.95

200

Shepherd's population has been growing at a rate of 0.2% each year.  If the population was 4,230 in 1990, what is the projected population for 2030?

Write the equation.

Growth

y=4,230(1+0.002)^40

200

A city is losing population at a rate of 0.5% each year.  If they had 405,000 in 2000, what was the population in 2020?

366,367 people

200

At an accounting firm, employees can expect to receive a 3.5% raise for each year they are employed.  If an employee began with a salary of $43,000, how much will their salary be after 15 years with the company?

$72,040.00

200

You want to go on a trip that will cost $3,000.  If you put $2,000 into an account that gains interest monthly at a rate of 2.8%, will you have enough for your trip in 5 years?  How much will you have?

No, you will only have $2,300.17.

300

The air in a bike tire leaks at a rate of 1% each hour.  If it began with 25 cubic inches of air, how much air will be remaining in 12 hours?

Write the equation.

Decay

y=25(1-0.01)^12

300

From 1900 to 1985, the population of Chicago increased its population by 2% each year.  If the population in 1900 was 520,000, what was the population in 1985?

2,799,097 people

300

The value of a collector's item increases an average of 2% each year.  If someone bought it in 2001 for $500, what will the value be in 2025?

$804.22

300

You start a savings account for your child by putting $1,500 into an account that compounds semi-annually at a rate of 5%.  How much will be in the account in 18 years?

$3,648.80

400

At an accounting firm, employees can expect to receive a 3.5% raise for each year they are employed.  If an employee began with a salary of $43,000, how much will their salary be after 15 years with the company?

Write the equation.

y=43,000(1+0.035)^15

400

The population of African elephants has decreased by 1% each year.  If the population in 1995 was 42,000, how many elephants were there in 2003?

38,755 elephants

400

Tuition has raised 2% at MSU each year since 2010.  If the tuition then was $17,000 a year, what is the tuition expected to be in 2025?

$22,879.76

400

You start a savings account with an inheritance you got in the amount of $40,000.  If you invest it into an account that compounds 3.5% quarterly, how much will be available to you in 20 years?

$80,305.23

500

The value of a collector's item increases an average of 2% each year.  If someone bought it in 2001 for $500, what will the value be in 2025?

Write the equation.

Growth

y=500(1+0.02)^24

500

The population of Garnet, MT decreased 12% each year from 1910 to 1930.  If they had 600 people to start with, how many were left?

47 people.

500
During the recession, the value of most homes fell by 1.2% a year, how much would a $400,000 home be after 3 years of recession?

$385,772.11

500

An account was started in 2004 that had $3,200.  It accrues interest at a rate of 6.8% and compounds monthly.  If the account holder wants to know what the value would be in 2030, how would you find it?

Write the equation.

Solve.

A=3,200(1+(0.068/12))^(12*26)

$18,655.86