20% of 50 is what number? THE 3 TYPES OF BASIC PERCENT PROBLEMS.20( )50=x 10 = x Number is 10 x = number 30% of 90 is what number? x = number.30( )90=x 27 = x Number is 27 % % %

20% of what number is 10? THE 3 TYPES OF BASIC PERCENT PROBLEMS.20( ) x=10 Number is x = number x = 50 % % % 6% of what number is 120? x = number.06( ) x= 120 Number is x = 2000

10 is what percent of 50? THE 3 TYPES OF BASIC PERCENT PROBLEMS 10( ) x =50 x = % x = number 30 is what percent of 80? 30( ) x =80 x = % x = number % % %

When an increase or decrease is expressed as a percent, it is called the PERCENT OF CHANGE. If the new number is greater than the original number, it is called the PERCENT OF INCREASE. If the new number is less than the original number, it is called the PERCENT OF DECREASE. PERCENT OF CHANGE

Bill buys a coat on sale for $40. The price before the sale was $50. What was the percent of decrease? PERCENT OF DECREASE = PERCENT OF CHANGE AMOUNT OF CHANGE = 50 – 40 =10

TRY THIS ONE: Mary earned $520 last week. This week she earned $380. What was her percent of decrease? Round to the nearest tenth of a percent. PERCENT OF DECREASE = PERCENT OF CHANGE AMOUNT OF CHANGE = 520 – 380 =140

Roberto is buying a car for $23,000. After taxes, he actually pays $24,265. What was the percent of increase (tax rate)? PERCENT OF INCREASE = AMOUNT OF CHANGE =24,265 – 23,000 =1265 PERCENT OF CHANGE

ADDING SALES TAX 6% of $7.98 = Jerome buys a dinner for $7.98. What will he pay after adding a sales tax of 6%?. 06($7.98) = $ To what decimal place do we round the answer? $0.48 Now what? $ $0.48 = $8.46 PERCENT OF CHANGE Try multiplying $7.98 by 106%. What do you get?

ADDING SALES TAX - TRY THIS ONE 5.5% of $125 = Della bought a new coat for $125. What will she pay if a 5.5% sales tax is added?. 055($125) = $6.875 To what decimal place do we round the answer? $6.88 Now what? $125 + $6.88 = $ PERCENT OF CHANGE Try multiplying $125 by 105.5%. What do you get?

AMOUNT PAID AFTER DISCOUNT PERCENT OF CHANGE 25% of $78 = Judy buys a ring for $78. What will she pay after a discount of 25%?.25($78) =$19.50 Now what? $78 - $19.50 =$58.50 Try multiplying $78 by 75%. What do you get?

AMOUNT PAID AFTER DISCOUNT – TRY THIS ONE PERCENT OF CHANGE 15% of $34500 = Wilford buys a new pickup that usually costs $34,500. He is getting a 15% discount. What will he pay for the pickup (disregard taxes)..15($34500) =$5175 Now what? $ $5175 =$29325 Try multiplying $34500 by 85%. What do you get?

SOLVING FOR THE ORIGINAL AMOUNT PERCENT OF CHANGE x = original area Martha increased the flower area in her garden by 22%. She now has sq. ft. of flower area. What was the area before the increase? x +.22x = x = x = sq. ft. 1.22

SOLVING FOR THE ORIGINAL AMOUNT PERCENT OF CHANGE x = original number of stamps Charles decreased his stamp collection by 15%. He now has a collection of 12,920 stamps. How many stamps did he have originally? x –.15x = x = x = ,200 stamps.85

SOLVING FOR THE ORIGINAL AMOUNT PERCENT OF CHANGE x = original price TRY THIS ONE: Theresa bought a dress on sale for $ She knows that it was on sale for 20% off. What was the original price for the dress. x –.20x = x = x = $

DOUBLE CHANGES PERCENT OF CHANGE FIND THE SALE PRICE An MP3 player, originally priced at $82.98 is now on sale for 20% off. The sales tax is 6.5%. What will you have to pay for the MP3 player?.20(82.98) = – = (66.38) = 4.31 $70.69 THEN FIGURE THE TAX = 70.69