1. 3-7 PERCENT EQUATIONS MISS BATTAGLIA – ALGEBRA 1 CP OBJECTIVE: USE EQUATIONS TO SOLVE PROBLEMS INVOLVING PERCENTS AND FIND SIMPLE INTEREST.

2. WARM UP

3. QUICK REVIEW!!!

4. SYMBOLS REPRESENT WORDS is of what = x n What is 40% of 8? n =.40 x 8

5. WRITE AN EQUATION TO MODEL EACH QUESTION. 1)What is 25% of 12? 2)3 is 75% of what? 3)What percent of 44 is 11? 4)16% of what is 200?

6. SALES Suppose you work at a computer store. You earn 5% commission on everything you sell. How much do you earn on a computer you sell for $1900.

7. SURVEYS In a survey, 1650 students said that drug abuse is the number one problem in the world today. How many students were surveyed?

8. THINK ABOUT IT… Can percents be numbers greater than 100? If yes, give an example.

9. EXAMPLE Suppose SHS requires 36 hours of community service. You spent 56 hours volunteering at a hospital. What percent of the requirement have you fulfilled?

10. SIMPLE INTEREST Today banks use compound interest, which we will study in Chapter 8. Compound interest is based on simple interest. Its formula is I = prt. (I = interest, p = principal, r = rate per year, t = time in years) Ex: I = ? if p = $340, r = 6%, t = 3 yr

11. FINANCE Suppose you invested $900 for two years. You earned $67.50 in simple interest. What was the annual rate of interest?

12. HOMEWORK Pg 142-143 # 2, 4, 5, 8, 9, 11, 12, 13, 20, 22, 23, 27, 36, 38