Percent to Decimal
Variables
Word Problems
Determine the Value
Half-Life
100

35%

0.35

100

What does r stand for?

Interest rate

100

You put $550 in a savings account.  It is compounded monthly at 4.5%.  How much will it be worth in 30 years?

$2,116.23

100

A coin had a value of $1.17 in 1995. Its value has been increasing at 9% per year. What is the value after 5 years?

$1.80

100

Write the formula for the "half-life" formula

A=P(0.5)^(t/h)

200

6.7%

0.067

200

You put $500 in an account.  It earns 6% interest compounded monthly.  How much will it be worth in 10 years?

What is the principal?

$500

200

Lance put $950 in an account that is compounded quarterly at 3%.  How much will it be worth in 5 Years?

$1,103.12

200

Gina deposited $1500 in an account that pays 4% interest compounded quarterly. What will the balance be in 2 years?

$2052.85

200

The half-life of radon-222 is 3.8 days. How much of a 100 g sample is left over after 15.2 days?

What is 6.25 g?

300

10%

0.10

or, even better: 0.1

300

You put $500 in an account.  It earns 6% interest compounded monthly.  How much will it be worth in 10 years?

What would the "t" number be?

10

300

Jerry put $150 in an account that is compounded annually at 13%.  How much will it be worth in 15 Years?

$938.14

300

Determine the amount of interest earned on a $2500 investment if it is invested at 5.25% annual interest compounded monthly for four years.

$29147.48

300

An isotope of cesium (cesium-137) has a half life of 30 years. If 1.0g of cesium-137 disintegrates over a period of 90 years. How many grams of cesium-137 remain?

What is 0.125g?

400

0.5%

0.005

400

You put $500 in an account.  It earns 6% interest compounded monthly.  How much will it be worth in 10 years?

What is the rate?

6%

400

Carrie put $1,050 in an account that is compounded quarterly at 10.5%.  How much will it be worth in 8 Years?

$2,405.97

400

Determine the amount of interest earned on a $100,000 investment if it is invested at 5.2% annual interest compounded quarterly for 12 years.

$1,139,608.06

400

The doctor gave you 700 milligrams of a drug. It has a half life of 4.5 hours. How much of the drug is in your bloodstream after 2 days?

What is 0.43 milligrams 

(remember to convert to hours!)

500

0.025%

0.00025

500

You put $500 in an account.  It earns 6% interest compounded monthly.  How much will it be worth in 10 years?

What would the "n" number be?

12

500

Morgan put $10,750 in an account that is compounded quarterly at 8%.  How much will it be worth in 12 Years?

$27,811.01

500

Determine the final account balance of an investment if $300 is invested at an interest rate of 6.75% compounded semiannually for 20 years.

$4091.07

500

A radioactive isotope has a half life of 2.37 years. How much of the sample did we start with if it took 8.2 years to reach 82 grams?

What is 902.3 grams