Unit 3 - Unit Rates and Percentages

Front

What is a unit rate?

Back

A unit rate is a comparison of two different quantities where one of the quantities is expressed as a quantity of one. For example, if a car travels 300 miles in 5 hours, the unit rate is 60 miles per hour.

Front

How do you calculate a percentage?

Back

To calculate a percentage, divide the part by the whole and then multiply by 100. For example, if 20 out of 50 students passed a test, the percentage is (20/50) * 100 = 40%.

Front

What is the formula to find the cost per ounce?

Back

To find the cost per ounce, divide the total cost of the item by the number of ounces. For example, if a 20 oz bag of fertilizer costs $10, the cost per ounce is $10 / 20 oz = $0.50 per ounce.

Front

If 30% of a class of 40 students are girls, how many girls are in the class?

Back

To find the number of girls, multiply the total number of students by the percentage: 40 * 0.30 = 12 girls.

Front

What does it mean if a percentage is greater than 100%?

Back

A percentage greater than 100% indicates that the part is larger than the whole. For example, if a student scores 110 out of 100 on a test, it means they earned extra credit.

Front

How do you convert a fraction to a percentage?

Back

To convert a fraction to a percentage, divide the numerator by the denominator and multiply by 100. For example, 3/4 = (3 ÷ 4) * 100 = 75%.

Front

What is the relationship between percentages, fractions, and decimals?

Back

Percentages, fractions, and decimals are different ways to represent the same value. For example, 50% = 0.5 = 1/2.

Front

If a shirt is on sale for 25% off and costs $40, what is the sale price?

Back

To find the sale price, calculate 25% of $40, which is $10. Then subtract that from the original price: $40 - $10 = $30.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if 1/2 = 2/4, then these two ratios are in proportion.

Front

How do you find the total number of items if you know the percentage of a part?

Back

To find the total number of items, divide the part by the percentage (in decimal form). For example, if 15 is 30% of the total, then total = 15 / 0.30 = 50.