Algebra 8-1  Compound Interest

 

1.         If you deposit $800 in an account that pays an annual yield of 5%,

            how much will you have in the account after:

            a.) 2 years        _______                      b.)  3 years       ________

 

            c.)  5 years       _______                      d.)  10 years     ________

 

            e.)  20 years     _______                      f.)  50 years      ________

 

            g.)  100 years (like you will be around)  __________

 

 

2.         Joe, Tom, and Rick are each going to open a savings account at the

            Bank of Hickam.  The Bank of aHickam offers an annual yield of 8%. 

           

            a.)  How much will each have in his won account after 9 years if

                  Joe invests $1, Tom $500, and Rick $3000. 

 

            Joe = ______               Tom = ________         Rick = __________

 

 

            b.)  Looking closely at the numbers, approximate by how much each

                  persons account got multiplied.

                                                                        ____________

 

            c.)  What does this tell you about any amount of money that you

                   invest at 8% for 9 years.

                                                            ____________________________

 

            d.)  Without calculating it, about how much would $7,000 become if

                   invested at 85 for 9 years?

                                                            ________________

 

3.         Fill in the table below for investing $10,000 at the given rates and years.

            Round answers to the nearest dollar.

 

$10,000

2%

3%

5%

8%

10%

3 years

 

 

 

 

 

5 years

 

 

 

 

 

10 years

 

 

 

 

 

15 years

 

 

 

 

 

 

 

 

 

 

 

 

 

4.         Is it better to invest at 6% for 5 years or 5% for 6 years?  Why?

 

 

 

 

5.         If you invest P dollars at 8% interest for 12 years, by how much

            will your P dollars have been multiplied?

                                                                                    _________

 

6.         On your TI-83 Plus calculator go to Y= and type in Y1 = 1000 (1.09)^x.

            Now go to Tblset (above your window button).  Set your TblStart to 0

            and your ΔTbl to 1.  Now hit the Table button (above your graph key).

            Using your arrow keys, scroll down the screen to find the following.

 

            a.)  How many years until you will have about $2000? _________

 

            b.)  How many years until you will have about $2800? _________

 

            c.)  How many years until you will have about $4000? _________

 

            d.)  How many years until you will have about $5600? _________

 

 

7.         Repeat Question 6 above, but instead of typing Y1 = 1000 (1.09)^x,

            type Y1 = (1.09)^x. 

 

            a.) How long until you have twice as much as your original investment? _____

 

            b.) How long until you have about three times

                 as much as your original investment?             _________

 

            c.) How long until you have about four times

                 as much as your original investment?             _________

 

            d.) How long until you have about eight times

                 as much as your original investment? _____