Lesson 7 1 4 Percentage Change Formula NEW

Lesson 7. 1. 4 Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

GUIDED PRACTICE #1 YOU TRY #1 The average fine for entering a National Forest Wilderness without a permit increased from $65 to $78. What is the rate of increase? A pair of snow boots at an equipment store originally cost $36. The boots are on sale for $60. What is the rate of increase? Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

GUIDED PRACTICE #2 YOU TRY #2 An employee’s hourly raise went up from $10 to $12 per hour. What is the rate of increase? Bruce’s hourly rate increased from $15. 50 to $18. 60. What is the rate of increase? Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

GUIDED PRACTICE #3 YOU TRY #3 A math book at a college bookstore originally cost $84 to purchase. If it is sold for $126, what is the percent markup on the book? A manager’s salary increased from $48, 000 to $51, 360. What is the rate of increase? Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

Cronnelly

GUIDED PRACTICE #4 YOU TRY #4 The selling price of a home was dropped from $200, 000 to $190, 000. By what percent did the price drop? A DVD recorder is marked down from $400 to $350. By what percent did the price drop? Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

GUIDED PRACTICE #5 YOU TRY #5 A stereo system is marked down from $450 to $382. 50. Skis at a sports store are on sale for $476. If the original price was $560, what discount rate does this represent? What is the discount percent? Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

GUIDED PRACTICE #6 YOU TRY #6 An exterior door regularly sells for $360. It is on sale for $288. What rate of decrease does this represent? Gas prices after September 11, 2001 went as high as $4. 00 a gallon. Prices have dropped to $2. 21 a gallon. What is the percent of decrease? Percentage Change Formula NEW VALUE – OLD VALUE = X OLD VALUE 100 Cronnelly

Percentage of Error Cronnelly

GUIDED PRACTICE #7 YOU TRY #7 Jessie estimates the weight of her cat to be 10 pounds. The actual weight of the cat is 13. 75 pounds. What is the percentage of error for Jessie’s cat’s weight? Marcus estimates that 230 people will attend the choir concert. The actual total that attended was 300 people. What is the percentage of error for the number of people who attended the choir concert? Cronnelly

GUIDED PRACTICE #8 YOU TRY #8 Eva estimates that 475 songs will fit on her MP 3 player. The actual amount of songs that fit is 380. Find the percent error. Dennis wants to buy a card for his wife Tina. Dennis calculates the amount of the card as $4. 50. The actual price of the card is $4. 00. Find the percent error Dennis made. Cronnelly

GUIDED PRACTICE #9 YOU TRY #9 Elana’s math class had 24 students yesterday. She miscounted the class total and recorded it as 20 students. What is Elena’s percent error? Sabrina calculates the cost of a book as $50. The actual price was $56. What is Sabrina’s percent error? Cronnelly