Digits, Grade 8, Volume 2, Homework Helper
• 6. Mariah deposits \$350 each month into an account that earns 2.4% annual interest compounded monthly. The table shows the approximate account balance at the end of each year.

• a. What percent of Mariah's balance is due to interest at the end of year 3? Round to the nearest tenth of a percent.

• b. What percent of Mariah's balance is due to interest at the end of year 5? Round to the nearest tenth of a percent.

• c. Does the percent of the balance due to interest increase or decrease over time?

• 7. Think About the Process Ella opens a savings account on February 1 by depositing \$45.00. She deposits another \$45.00 on the first day of each month. The account earns 3.3% annual interest compounded monthly.

• a. How do you find the ending balance for each month after the first month?

• b. Copy and complete the table to find the balance at the end of each month through May.

• 8. Think About the Process Andrea deposits \$180 each month into an account that earns 3.6% annual interest compounded monthly. The table shows the account balance at the end of each year to the nearest dollar.

• a. Write an expression for the total interest earned after n years.

• A. open . cap balanceafteryear . n close minus , open180close , , open12close , n

• B. fraction cap balanceafteryear . n , over open 180 close open 12 close n end fraction

• C. fraction cap balanceafteryear . n , over n end fraction . middle dot open 180 close open 12 close

• D. fraction open 180 close open 12 close n , over cap balanceafteryear . n end fraction

• b. By the end of the fifth year, what amount of interest does the account earn?

• 9. Open-Ended The table shows the approximate account balance at the end of each year. The account earns 1.2% annual interest compounded monthly. Each month, Julia deposits \$300.

• a. What percent of the balance at the end of the fifth year is due to the monthly deposits? Round to the nearest tenth of a percent.

• b. Make a prediction about the percent of the balance due to deposits at the end of the sixth year. Explain how you made your prediction and what you would need to do to check its accuracy.

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