A store advertises 25% off a $30 shirt. What is the sale price
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A store advertises 25% off a 30 dollar shirt. What is the sale price? When we see 25% off, it means the customer pays 75% of the original price. Let's visualize this scenario with a shirt priced at 30 dollars with a 25% discount.
Method one: Calculate the discount amount first. To find 25 percent of 30 dollars, we convert 25 percent to a decimal, which is 0.25, and multiply by 30. This gives us 7.50 dollars discount. Then we subtract this from the original price: 30 minus 7.50 equals 22.50 dollars. So the sale price is 22 dollars and 50 cents.
Method two: Calculate the sale price directly. If 25 percent is taken off, then we're actually paying 75 percent of the original price. So we can calculate 75 percent of 30 dollars directly. Converting 75 percent to a decimal gives us 0.75. Multiplying 0.75 by 30 gives us 22.50 dollars. This is the same result as method one, but with one less step.
Let's visually verify our calculations with a bar chart. The blue bar represents the original price of 30 dollars. This is divided into two parts: the red bar showing the discount amount of 7 dollars 50 cents, and the green bar showing the sale price of 22 dollars 50 cents. As we can see, 7.50 plus 22.50 equals exactly 30, confirming our calculations are correct.
Let's practice with more examples. First: 20 percent off 45 dollars. Using method one, we calculate 20 percent of 45, which is 0.20 times 45, equaling 9 dollars discount. Then 45 minus 9 equals 36 dollars sale price. Using method two, we calculate 80 percent of 45, which is 0.80 times 45, also equaling 36 dollars. Second example: 30 percent off 80 dollars. Method one: 30 percent of 80 is 24 dollars discount, so 80 minus 24 equals 56 dollars. Method two: 70 percent of 80 is also 56 dollars. Third example: 15 percent off 60 dollars. Method one: 15 percent of 60 is 9 dollars discount, so 60 minus 9 equals 51 dollars. Method two: 85 percent of 60 is also 51 dollars.
These percentage discount calculations have real-world applications in everyday shopping. When you're at a store with multiple items on sale, you can quickly estimate the total cost. Method one is good for understanding exactly how much you're saving. Method two is often more efficient for quick mental calculations. For example, if you have three items in your cart: a 40 dollar item with 20 percent off, a 30 dollar item with 30 percent off, and a 50 dollar item with 15 percent off, you can calculate the sale prices as: 40 times 0.8 equals 32, 30 times 0.7 equals 21, and 50 times 0.85 equals 42.50. Adding these together gives a total of 95 dollars and 50 cents. This skill helps you budget effectively and verify that the cashier has applied discounts correctly.