1. Lesson 7.1.4 Percentage Change Formula NEW VALUE – OLD VALUE = X
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2. GUIDED PRACTICE #1
The average fine for entering a National Forest Wilderness without a permit increased from $65 to $78. What is the rate of increase?
YOU TRY #1
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
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3. GUIDED PRACTICE #2
An employee’s hourly raise went up from $10 to $12 per hour. What is the rate of increase?
YOU TRY #2
Bruce’s hourly rate increased from $15.50 to $ What is the rate of increase?
Percentage
Change Formula
NEW VALUE – OLD VALUE = X
OLD VALUE
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4. 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?
YOU TRY #3
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
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5. Cronnelly

6. GUIDED PRACTICE #4
The selling price of a home was dropped from $200,000 to $190,000. By what percent did the price drop?
YOU TRY #4
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
Cronnelly

7. A stereo system is marked down from $450 to $382.50.
GUIDED PRACTICE #5
A stereo system is marked down from $450 to $
What is the discount percent?
YOU TRY #5
Skis at a sports store are on sale for $476. If the original price was $560, what discount rate does this represent?
Percentage
Change Formula
NEW VALUE – OLD VALUE = X
OLD VALUE
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8. GUIDED PRACTICE #6
An exterior door regularly sells for $360. It is on sale for $288. What rate of decrease does this represent?
YOU TRY #6
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
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9. Percentage of Error
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10. GUIDED PRACTICE #7 YOU TRY #7
Jessie estimates the weight of her cat to be 10 pounds. The actual weight of the cat is pounds. What is the percentage of error for Jessie’s cat’s weight?
YOU TRY #7
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?
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11. GUIDED PRACTICE #8
Eva estimates that 475 songs will fit on her MP3 player. The actual amount of songs that fit is Find the percent error.
YOU TRY #8
Dennis wants to buy a card for his wife Tina. Dennis calculates the amount of the card as $ The actual price of the card is $ Find the percent error Dennis made.
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12. YOU TRY #9 GUIDED PRACTICE #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?
YOU TRY #9
Sabrina calculates the cost of a book as $50. The actual price was $56. What is Sabrina’s percent error?
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