Unit 6
Percent’s
Name ______Class______
Review of Percent’s, Decimals, and Fractions
Percent as a Decimal
1.8%2.25%3.10%
4.1%5.38.5%6.6.75%
7.40%8..5%9.2.3%
10.35%11.8.75%12.5%
13.4.785%14.100%15.175%
Decimalas aPercent
1..252.13..95
4..045..07356..3
7..0258..4589.1.25
10.5.511..00612..084
13..5614..08815..0975
Percent of a Number
OF means to MULTIPLY
1.Find 5% of 300.2.Find 25% of 180.
3.What is 40% of 70?4.What is 15% of 100
5.55% of 1606.75% of 280
7.120% of 758.150% of 28
9.160% of 3510.100% of 85
11.If 275 students took the survey, how many can be
expected to have 3 televisions each in their houses?
(Think 23% of 275)
12. Mr. Sudimack earned a 4% commission on the sale of a hot tub that costs $3,755. How
much did he earn? (Think 4% of $3,755)
13. Mackenzie wants to buy a backpack that costs $50. If the tax rate is 6.5%, how much tax
will she pay? (Think 6.5% of $50)
Parts of a Whole
1.What percent of 25is 20?2.$12.75 is what percent of $50?
3.What is 5% of 60?4.12% of 85is what number?
5.40% of what number is 26?6.84 is 75% of what number?
7. The average male Western Lowland gorilla eats about 33.5 pounds
of fruit each day. How much food does the average adult male
gorilla eat each day?
8.What percent of $90 is $9?9.What number is 2% of 35?
10.Brand A cereal contains 10 cups of cereal. How many more cups
of cereal are in Brand B cereal?
Percent as an Equation
You can use the percent equation to solve problems that involve percent.
3 is 50% of 6
Write an equation for each problem. Then solve.
a.What is 6% of 200?b. Find 72% of 50c. What is 14% of 150?
d.21 is what percent of 40?e. What percent of 40 is 9?
f. 27 is what percent of 150?g. 13 is 26% of what number?
Round to the nearest tenth if necessary.
h. 39 is 84% of what number?i. 26% of what number is 45?
j.A survey found that 25% of people aged 18-24 gave up their home phone and only use a cell phone. If 3,264 people only use a cell phone, how many people were surveyed?
Percent Change
Increase/Decrease
Example
Find the percent change in the cost of gasoline from 1970 to 2010.
Round to the nearest whole percent if necessary.
a. Yusuf bought a DVD recorder for $280. Now, it is on sale for $220. Find the percent change
in the price. Round to the nearest whole percent.
b. Find the percent of change from 10 yards to 13 yards.
c.The price of a radio was $20. It is on sale for $15. What is the percent of change in the
price of a radio?
d.Ahmed wants to practice free-throws. He estimates the distance from the free-throw line to the hoop and marks it with chalk. Ahmed’s estimate was 13.5 feet. The actual distance should be 15 feet. Find the percent error.
g. Jessie estimates the weight of her cat to be 10 pounds. The actual weight of the cat is 13.75 pounds. Find the percent error.
Sales Tax and Tips
Example
Alonso plans to buy a new kayak that costs $2,100. But when he buys the kayak, it actually costs more because he lives in a county where there is a 7% sales tax. Sales tax is 7% of $2,100.
a. Drew wants to buy exercise equipment that costs $140 and the sales tax is 5.75%. What is
the total cost of the equipment?
b. What is the total cost of a sweatshirt if the regular price is $42 and the sales tax is 5½ %?
c. A customer wants to tip 15% on a restaurant bill that is $35. What will be the total bill
with tip?
d. A haircut costs $20. Sales tax is 4.75%. Is $25 sufficient to cover the haircut with tax and a
15% tip?
e. Scott wants to tip his taxicab driver 20%. If his commute costs $15, what is the total cost?
f. Find the total cost of a spa treatment of $42 including 6% tax and 20% tip.
Mark- Up
When you own a store, you purchase items from the manufacturer and then “mark-up” the price to sell it. The difference between what you sell the item for and what you bought it for is your profit.
Example
You own a boutique. You purchased the following items from a clothing manufacturer and marked them up by 30%.
ItemPurchase PriceMark UpSelling Price
Jeans$12 each
Sweater$25 each
Skirt$15 each
Dress Pants$18 each
If you sold one of each item above what would the total profit be?
1.If the cost to make bracelets is $5 each and you want to profit $2 on the sale of each bracelet. What is your mark-up as a percent on each bracelet?
2.You bought popular toy on sale for $20 and want to sell it on EBay. You want to mark up the toy 60%. What did you sell it for?
3.What was the mark-up on a $217.50 item if the purchase price was $150 (in dollars and as a %).
4.Growing up, you lived in a small town. When you left for college, the population was 840. You recently heard that the population has grown by 15%. What is the population now?
Discount
Example
A DVD normally costs $22. This week it is on sale for 25% off the original price. What is the sale price of the DVD? Discount is 25% of the price. Discount acts like a coupon.
a. A shirt is regularly priced at $42. It is on sale for 15% off of the regular price. What is the
sale price of the shirt?
b. A boogie board that has a regular price of $75 is on sale at a 35% discount. What is the sale
price with 7% tax?
c. A CD that has a regular price of $15.50 is on sale at a 25% discount. What is the sale price
with 6.5% tax?
d. A cell phone is on sale for 30% off. If the sale price is $239.89, what is the original price?
e. Clothes Are Us and Ratcliffe’s are having sales. At Clothes Are Us, a pair of sneakers is on
sale of 40% off the regular price of $50. At Ratcliffe’s, the same brand of sneakers is
discounted by 30% off of the regular price of $40. Which store has the better sale price?
Commission
Commission is the money paid to you when you sell a product or service for a company. Sometimes you earn an hourly wage plus commission. Sometimes instead of paying you a certain hourly or weekly salary, companies pay the workers for what they sell, or a straight commission.
Example
Jimmy is a salesman at Amy’s Furniture. He earns a base salary of $350 per week plus 6% commission on sales. What was Jimmy’s weekly salary if his total sales for the week were $7500?
1.Carol sells candles and Yankee Candle. She earns $8.50 per hour plus 6% commission on sales. Last week Carol worked 40 hours. What was Carol’s weekly gross salary if her total sales were $250?
2.Ben earns straight commission as a real-estate agent. Last month his total sales for all the houses he sold were $950,000. If Ben earns a 3% rate of commission, what was his gross income last month?
3.Jenna earns straight commission selling cell phone contracts. Last month she sold 210 cell phone contracts worth a total of $29,950. If Jenna earns an 8% rate of commission, what was her gross income last month?
4.Julie sells jewelry at house parties as a way to make extra money. Her commission is 11% of the sales she makes. She had 3 parties this month. The sales for the 3 parties were $810, $670, and $925. What was her commission for the month?
Simple Interest
Prinicpal - ______
Interest - ______
Example
Mrs. Ramirez is investing $400 in a savings account at a simple interest rate of 2% to purchase a laptop computer. She plans on investing the money for 5 years.
Principal = Rate = Time = years
a. Arnold puts $580 into a savings account. The account pays 3% simple interest. How much
interest will he earn in each amount.
i)5 yearsii)6 months
b. Jenny puts $1,560 into a savings account. The account pays 2.5% simple interest. How
much will she earn in 3 years?
c. Marcos invests $760 into a savings account. The account pays 4% simple interest. How
much interest will he earn after 5 years?
Practice with a partner.
1.Mrs. Hanover borrows $1,400 at a rate of 5.5% per year. How much simple interest will she pay if it takes 8 months to repay the loan?
2.An office manager charge $425 worth of office supplies on a credit card. The credit card has an interest rate of 9.9%. How much money will he owe at the end of one month if he makes no other charges on the card and does not make a payment?
3.Maggie is taking out a student loan for $2,600. She plans on paying off the loan in 3 years. At the end of 3 years, Maggie will have paid $390 in interest. What is the simple interest rate on the student loan?
4.The Masters family financed a computer that cost $1,200. If the interest rate is 19%, how much will the family owe for the computer after one month if no payments are made?
5.Samantha received a loan from the bank for $4,500. She plans on paying off the loan in 4 years. At the end of 4 years, Samantha will have paid $900 in interest. What is the simple interest rate on the bank loan?
Parts of a Whole
There are 1200 students in a school. 1/5 of the students are majoring in Science. Of the science majors 30% are Biology majors. Of the Biology majors, 2/3are Marine Biology majors. How many of students in the school are Marine Biology majors?
1.A clothing store sells scarves in different colors. The table shows the colors of the last 200 scarves sold.
The manager plans to order 1800 new scarves for all of the stores in the region. How many of each color should she order?
RedBlueGreen
YellowPurpleWhite
The purchasing manager wants to order 12,000 scarves for the U.S. How many of each color should she order?
RedBlueGreen
YellowPurpleWhite
Percent Increases and Decreases
Next to each number write percent “increase” or “decrease” and then write the percent increase or decrease.
Example
a.1.075______b..75______
Try these on your own.
1.1.06______2..40______
3.1.04______4.1.015______
5..65______6..33______
7..85______8.1.03______
9.1.025______10..90______
11..50______12..55______
13.1.0875______14.1.10______
15..60______16.1.01______
17..45______18.1.4______
19.1.02______20.1.2______
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