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3-7 Percent of Change. Objective: Find percent of increase or decrease. What is it?. When an increase or decrease is expressed as a percent, the percent is called the percent of change Percent of increase: if the number is greater than the original amount
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3-7 Percent of Change Objective: Find percent of increase or decrease
What is it? • When an increase or decrease is expressed as a percent, the percent is called the percent of change • Percent of increase: if the number is greater than the original amount • Percent of decrease: if the number is less than the original amount
Example • Original: 25 new: 28 How do we get it into a percentage? Multiply by 100 =12%
Example • Original 30 new: 12 Therefore 60% Increase or decrease?
Example The field used by the NFL is 120 yards long. The length of the field used by the CFL is 25% longer then the one used by the NFL. What is the length of the field used by the CFL? • Let l= the length of the CFL field. Since 25% is a percent of increase, the length of the NFL field is less then the length of the CFL field. Therefore, l – 120 represents the amount of change.
Continued The length of the field used by the CFL is150 yards
Example A concert ticket costs $45. If the sales tax is 6.25%, what is the total price of the ticket? The tax is 6.25% of the price of the ticket. 6.25% of $45=.0625 x 45 2.8125 $2.81 Add this to the original price 45.00+2.81=$47.81