1. Do Now 2/21/12 Take out HW from last night. Take out HW from last night. Text p. 248, #7-16, 19 & 20 Text p. 248, #7-16, 19 & 20 Copy HW in your planner. Copy HW in your planner. Text p. 256, #5-18 all Text p. 256, #5-18 all Quiz sections 6.4-6.6 Wednesday Quiz sections 6.4-6.6 Wednesday Did you hand in POTW #9? Did you hand in POTW #9?

2. Homework Text p. 248, #7-16, 19 & 20 7) 37.5% 7) 37.5% 8) 63.6% 8) 63.6% 9) 22.2% 9) 22.2% 10) 8.7% 10) 8.7% 11) $55.25 11) $55.25 12) $199.75 12) $199.75 13) 100% 13) 100% 14) 4.8% 14) 4.8% 15) 43.6% 15) 43.6% 16) 69.2% 16) 69.2% 19) 56.25 19) 56.25 20) $8.96 20) $8.96

3. Objective SWBAT compute simple interest SWBAT compute simple interest

4. the amount of money charged for borrowing or using money. the amount of money charged for borrowing or using money. Section 6.6 “Simple Interest” INTEREST-

5. the product of the principal, the annual interest rate, and the time in years. the product of the principal, the annual interest rate, and the time in years. Principal – the amount borrowed, loaned, or in savings. Rate of interest – the percent charged or earned. Time in years – when time is less than a year, write time as a fraction of the year. SIMPLE INTEREST- I=P ∙ r∙ r∙ r∙ r ∙ t∙ t∙ t∙ t

6. Writing Time in Years… Time in years – when time is less than a year, write time as a fraction of the year. Write the months as a fraction of a year. 3 months7 months10 months

7. Simple Interest You have $3,000 in a savings account in a local bank. The annual interest rate is 3%. How much interest will the bank pay you in 4 years? Principal = $3000 Interest rate = 3% or 0.03 Time = 4 years

8. Simple Interest You borrowed $18,000 for a new car. The annual interest rate is 12%. What is the interest you will have to pay in two years to borrow this money? Principal = $18,000 Interest rate = 12% or 0.12 Time = two years or 2

9. Determining the Amount of Investment Time Isaiah invested $3,500 in a mutual fund at a yearly interest rate of 6%. He earned $945 in interest. For how long was the money invested? Principal = $3,500 Interest rate = 6% or 0.06 Interest = $945

10. Account Balance When an account earns interest it is added to the money in the account. The BALANCE (A) of an account that earns simple annual interest is the sum of the principal (P) and the interest (I). When an account earns interest it is added to the money in the account. The BALANCE (A) of an account that earns simple annual interest is the sum of the principal (P) and the interest (I). Balance Principal Interest

11. Computing Total Savings Nadia’s aunt deposited $325 into a savings account as a college fund. How much will be in the account after 8 years if the account earns simple interest of 7%? A = P+ I A = $325 + $182.00 A = $507.00 I = P ∙ r ∙ t I = P ∙ r ∙ t I = (325)(0.07)(8) I = (325)(0.07)(8) I = $182.00 I = $182.00 Calculate interest first.Find account balance.

12. Finding an Interest Rate Suppose you save $1400 in a savings account that earns simple annual interest. After 9 months, the balance in your account is $1421. Find the annual interest rate. Suppose you save $1400 in a savings account that earns simple annual interest. After 9 months, the balance in your account is $1421. Find the annual interest rate. Principal = $1400 Balance = $1421 Time = 9 months The interest rate is 2%

13. Homework Text p. 256, #5-18 all Text p. 256, #5-18 all 24

14. A shoe store in NJ has a sale on sneakers for 15% off. If the original price is$75 what is the total cost of the sneakers with tax? Sale price = Original price – Discount = – (15% · 75) = 75 – 11.25 = 75 $63.75 Total Price = Purchase Price + Sales Tax $63.75 + (63.75 x 7%) $63.75 + 4.46 $68.21