Compound Interest & Half Life Word Problems

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

Karla invested $1,000 in savings bonds. If the bonds earn 6.75% interest compounded semi-annually, how much total will Karla earn in 15 years?

• $1,584.62
• $2,651.39
• $2,706.86
• $1,825.10

Emily would like to buy some new furniture for her home. She decides to buy the furniture on credit with 9.5% interest compounded quarterly. If she spent $7,400, how much total will she have paid after 8 years.

• $15,415.94
• $15,683.28
• $15,927.56
• $16,109.05

Jay'den earned $475 from mowing lawns last summer. He deposited this money in an account that pays an interest rate of 3.8% compounded annually. What will be his balance after 15 year?

• $827.52
• $831.10
• $839.45
• $846.80

Courtney saved up $2,200 working as a waitress over the summer. She put this money into a bank account that earned 5.2% interest and is compounded daily. How much will she have in her account at the end of 4 years?

• $2201.25
• $2694.55
• $2707.45
• $2708.63

If 10 mg of iodine 131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.

• 1.25mg
• 1.25g
• 10g
• 10mg

The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g?

• 3.0g
• 0.25mg
• 0.3g
• 0.25g

You have 100 grams of radioactive C-14. The half life of C-14 is 5730 years. 
How many grams are left after 1 half life? 

• 100 grams
• 25 grams
• 2 grams
• 50 grams

What would be the "a" value (initial value) for this problem?

A local zoo has a population of 32 meerkats. They are doubling every 5 years. How many would there be in 10 years?

• 32

• 2

• 5

• 10