Percents: Percentages in Real Life (2023)

Lesson 3: Percentages in Real Life

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Sales tax

Depending on where you live, you might pay a sales tax on the things you buy. A sales tax is an extra charge added to the price of an item. The amount you pay in tax is almost always a percentage of that price.

Suppose you buy a $50 coffeemaker in an area where the sales tax is 8%. When you check out, 8% of $50 would be added to your total price. How much would you pay total?

Click through the slideshow to learn how to calculate sales tax.

  • Percents: Percentages in Real Life (1)

    Let's say you want to buy a $50 coffeemaker, and the sales tax is 8%.

  • Percents: Percentages in Real Life (2)

    Sales tax is a percentage of the price of the item. This means the sales tax is eight percent of fifty dollars.

  • Percents: Percentages in Real Life (3)

    Whenever you see the phrase "of something" in a math sentence, it's usually a hint that you'll need to multiply.

  • Percents: Percentages in Real Life (4)

    So we'll multiply 50 by 8%.

  • Percents: Percentages in Real Life (5)

    Before we can do that, we'll need to convert 8% into a decimal.

  • Percents: Percentages in Real Life (6)

    We'll move the decimal point two places to the left...

  • Percents: Percentages in Real Life (7)

    We'll move the decimal point two places to the left...so 8% becomes 0.08.

  • Percents: Percentages in Real Life (8)

    Now we can multiply: 0.08 times 50 equals 4.00.

  • Percents: Percentages in Real Life (9)

    So the sales tax is $4.00. Another way to say this is that 8% of $50.00 is $4.00.

  • Percents: Percentages in Real Life (10)

    Remember, sales tax is an extra charge added to the price of an item. So we'll add the sales tax to our original price.

  • Percents: Percentages in Real Life (11)

    $4.00 plus $50.00 equals $54.00.

  • Percents: Percentages in Real Life (12)

    The final price of the coffeemaker is $54.00 after adding sales tax.

  • Percents: Percentages in Real Life (13)

    Let's try another example. Let's say you want to buy a six pack of soda that costs $4.50, and the sales tax on food is 4%.

  • Percents: Percentages in Real Life (14)

    This means the sales tax is 4% of $4.50.

  • Percents: Percentages in Real Life (15)

    So we'll multiply 4% by 4.50.

  • Percents: Percentages in Real Life (16)

    First, we need to convert 4% into a decimal, so we'll move the decimal point two places to the left.

  • Percents: Percentages in Real Life (17)

    4% is the same as 0.04.

  • Percents: Percentages in Real Life (18)

    Now we'll multiply: 4.5 times 0.04 is 0.18, so the sales tax is $0.18, or 18 cents.

  • Percents: Percentages in Real Life (19)

    We could also say that 4% of $4.50 is $0.18.

  • Percents: Percentages in Real Life (20)

    Finally, we'll add the sales tax to the original price.

  • Percents: Percentages in Real Life (21)

    4.50 plus 0.18 is 4.68.

  • Percents: Percentages in Real Life (22)

    So the final price is $4.68 after adding sales tax.

  • Percents: Percentages in Real Life (23)

Try This!

Find the total cost of each item after sales tax. Be sure to round your answer to the nearest cent. For example, $64.24305 would become $64.24.

You buy a pair of sunglasses for $49.00. The sales tax is 7%.

Percents: Percentages in Real Life (24)

You need to purchase $326.00 worth of vinyl siding. The sales tax is 4%.

Percents: Percentages in Real Life (25)

You buy $32.19 worth of groceries. The sales tax is 5.7%.

Percents: Percentages in Real Life (26)

Curious about the sales tax where you live?

You can use this list of State and Local Sales Tax Rates from the Tax Foundation to look up the sales tax rate where you live.

Discounts, markdowns, and sales

Have you ever bought something on sale marked down by twenty percent? Or used a coupon to take 30% off? If so, you've used a discount. A discount is usually a percentage of the original price. The percentage is subtracted from the original price to determine the sale price.

Let's say a shirt costs $8, but it's been marked down by 50%. When you check out, 50% of $8 will be subtracted from the original price. How much would the shirt cost after the discount?

Click through the slideshow to learn how to calculate discounts.

  • Percents: Percentages in Real Life (27)

    Let's say a shirt costs eight dollars, but it's on sale for 50% off.

  • Percents: Percentages in Real Life (28)

    This means it will cost fifty percent less than the original price, or half as much.

  • Percents: Percentages in Real Life (29)

    This discount is a percentage of the original price. Here, 50% off means the discount is 50% of $8.

  • Percents: Percentages in Real Life (30)

    50%, or half, of 8 is 4. This means the shirt will cost $4 less than the original price.

  • Percents: Percentages in Real Life (31)

    Remember, the discount is taken off of the original price. So we'll subtract the discount from the original price.

  • Percents: Percentages in Real Life (32)

    8 minus 4 is 4.

  • Percents: Percentages in Real Life (33)

    So the shirt would cost four dollars on sale.

  • Percents: Percentages in Real Life (34)

    Let's try another example. What if the same shirt was on sale for 20% off?

  • Percents: Percentages in Real Life (35)

    This means it would cost twenty percent less than the original price. This time, it'll take a few more steps to find the final price.

  • Percents: Percentages in Real Life (36)

    The discount is 20% of $8.

  • Percents: Percentages in Real Life (37)

    Whenever, you see the phrase "of something" in a math sentence, it's usually a hint that you'll need to multiply.

  • Percents: Percentages in Real Life (38)

    So we'll multiply 8 by 20%.

  • Percents: Percentages in Real Life (39)

    Before we can do that, we'll need to convert 20% into a decimal.

  • Percents: Percentages in Real Life (40)

    We'll move the decimal point two places to the left...

  • Percents: Percentages in Real Life (41)

    We'll move the decimal point two places to the left...so 20% becomes 0.20.

  • Percents: Percentages in Real Life (42)

    Now we can multiply. 8 times 0.20 equals 1.60.

  • Percents: Percentages in Real Life (43)

    Another way to say this is that 20% of $8.00 is $1.60.

  • Percents: Percentages in Real Life (44)

    The shirt will cost $1.60 less than the original price of $8. So we'll subtract the discount from the original price.

  • Percents: Percentages in Real Life (45)

    8.00 minus 1.60 equals 6.40.

  • Percents: Percentages in Real Life (46)

    So the shirt would cost $6.40 on sale.

  • Percents: Percentages in Real Life (47)

Try This!

Find the final cost for each item.

You find a pair of shoes on sale for 35% off. They originally cost $90.00. What will they cost on sale?

Percents: Percentages in Real Life (48)

You spend $42.00 on groceries, but you have a coupon for 10% off. What is the final price of your bill?

Percents: Percentages in Real Life (49)

A bookstore is going out of business, so all books are 60% off. How much would you spend on a book that originally cost $12.95?

Percents: Percentages in Real Life (50)

Calculating tips

If you've eaten at a restaurant, you've probably left a tip for your server. A tip is a small amount of money that you add to your bill when someone gives you service. The amount of a tip is usually a percentage of the total cost. For example, you might leave a fifteen percent tip at a restaurant for average service.

Let's say you eat at a restaurant with some friends. The bill comes to $12.04, and you'd like to leave a 15% tip. This means you'd like to leave 15% of $12.04. How much money should you leave total?

Click through the slideshow to learn how to calculate tips.

  • Percents: Percentages in Real Life (51)

    Let's say you went out to eat, and your bill is $12.04. You want to leave a 15% percent tip.

  • Percents: Percentages in Real Life (52)

    A tip is a percentage of the total. In this case, it means the tip is fifteen percent of $12.04.

  • Percents: Percentages in Real Life (53)

    Whenever you see the phrase "of something" in a math sentence, it's usually a hint that you'll need to multiply.

  • Percents: Percentages in Real Life (54)

    So we'll multiply 12.04 by 15%.

  • Percents: Percentages in Real Life (55)

    Before we can do that, we'll need to convert 15% into a decimal.

  • Percents: Percentages in Real Life (56)

    We'll move the decimal point two places to the left...

  • Percents: Percentages in Real Life (57)

    We'll move the decimal point two places to the left...so 15% becomes 0.15.

  • Percents: Percentages in Real Life (58)

    Now we can multiply. 0.15 times 12.04 equals 1.80.

  • Percents: Percentages in Real Life (59)

    So the tip is $1.80.

  • Percents: Percentages in Real Life (60)

    We could also say that 15% of $12.04 is $1.80.

  • Percents: Percentages in Real Life (61)

    Remember, a tip is extra money added to the total. So we'll add the tip to the bill.

  • Percents: Percentages in Real Life (62)

    1.80 plus 12.04 equals 13.84.

  • Percents: Percentages in Real Life (63)

    So the final price of the meal is $13.84, after including tip.

  • Percents: Percentages in Real Life (64)

    Let's try another example. Let's say you had excellent service and would like to leave a 20% tip for a meal that cost $68.80.

  • Percents: Percentages in Real Life (65)

    This means the tip will be 20% of $68.80.

  • Percents: Percentages in Real Life (66)

    We'll multiply 20% by 68.80.

  • Percents: Percentages in Real Life (67)

    First, we'll need to convert 20% into a decimal, so we'll move the decimal point two places to the left.

  • Percents: Percentages in Real Life (68)

    20% is the same as 0.20.

  • Percents: Percentages in Real Life (69)

    Now we'll multiply. 68.80 times 0.20 equals 13.76.

  • Percents: Percentages in Real Life (70)

    So the tip is $13.76.

  • Percents: Percentages in Real Life (71)

    Another way to say this is that 20% of $68.80 is $13.76.

  • Percents: Percentages in Real Life (72)

    Finally, we'll add the tip to the bill.

  • Percents: Percentages in Real Life (73)

    68.80 plus 13.76 equals 82.56.

  • Percents: Percentages in Real Life (74)

    The final price, after tip, is $82.56.

  • Percents: Percentages in Real Life (75)

Try This!

Find the final price for each item, including the tip.

You have a pizza delivered to your house. It costs $19. You want to leave the delivery driver a 15% tip. What's the total?

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You eat out at a restaurant with some friends. The bill comes to $47.50. If you leave a 20% tip, what is the total cost of your bill?

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Your cab fare from home to the airport is $35. You'd like to give your driver an 18% tip. What's the total?

Percents: Percentages in Real Life (78)

Percents: Percentages in Real Life (80)

Previous: Calculating Percentages

Next:Converting Percentages, Decimals, and Fractions

Percents: Percentages in Real Life (81)

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FAQs

Percents: Percentages in Real Life? ›

Percentages are used widely and in many different areas. For example, discounts in shops, bank interest rates, rates of inflation and many statistics in the media are expressed as percentages. Percentages are important for understanding the financial aspects of everyday life.

Where is percentage change used in real-life? ›

Calculating percent change is useful in various daily applications such as finance, sales, tax and inflation rate, physics and other fields of mathematics.

What is a real world example of a percentage increase? ›

The concert attendance went up by a whopping 110 people, so we divide that by the original number of attendees. Then we turn that into a percentage. Whoa. Attendance rose by 220%.

How are percents greater than 100% used in real world contexts? ›

The number of hot dogs you sell in the afternoon is 300% of the number you sold in the morning. It's three times as many. Here's another way of looking at this: You sell 20 more hot dogs in the afternoon than in the morning, so this is a 200% increase in the afternoon — 20 is twice as many as 10.

What are 3 real life examples of percentages? ›

Percentages are used widely and in many different areas. For example, discounts in shops, bank interest rates, rates of inflation and many statistics in the media are expressed as percentages. Percentages are important for understanding the financial aspects of everyday life.

What are some examples of when percentages are used? ›

Percentages are used in many real-life situations. Understanding them is important. Examples include bank interest, student loan interest, or taxes. In stores, sales tax and discounts are almost always shown as a percentage.

What is a real life example of percent composition? ›

Percentage composition can also come into play with air quality, combustion of fuels, and even popping popcorn! The percentage of water in the molecule is very important. If there is not enough water, the kernal won't pop. Percentage composition is a part of our daily lives even when we are unaware of it.

What is an example of a percentage difference? ›

For example, "25" and "75" would have a Percent Difference of 67%.

Why is percentage change more useful? ›

Usually you are going to be working with larger datasets and quantities, so it is more important to use the percentage change method because as you can see the percentage change method gives a more precise description as to how the data has changed over a period of time.

What is a real world example of a percent decrease? ›

Percent decrease refers to the percentage change in the value when it is decreased over a period of time. For example, a decrease in the level of rainfall, a decrease in the number of Covid patients, etc.

How do I solve for percentages? ›

2. How to find what percent of X is Y. Use the percentage formula: Y/X = P%
  1. Convert the problem to an equation using the percentage formula: Y/X = P%
  2. X is 60, Y is 12, so the equation is 12/60 = P%
  3. Do the math: 12/60 = 0.20.
  4. Important! ...
  5. Converting 0.20 to a percent: 0.20 * 100 = 20%
  6. So 20% of 60 is 12.

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