Proportions & Percentages

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

Front

How do you convert a percentage to a decimal?

Back

To convert a percentage to a decimal, divide the percentage by 100. For example, 25% becomes 0.25.

Front

What is the formula to find a percentage of a number?

Back

The formula to find a percentage of a number is: (percentage/100) * total number. For example, to find 20% of 50, calculate (20/100) * 50 = 10.

Front

If 30% of a number is 60, what is the number?

Back

To find the number, divide 60 by 0.30. The number is 200.

Front

What is the relationship between fractions and percentages?

Back

Fractions can be converted to percentages by multiplying the fraction by 100. For example, 1/4 = 0.25 = 25%.

Front

How do you find the total amount if you know the percentage and the part?

Back

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

Front

What is 50% of 80?

Back

50% of 80 is 40.

Front

How do you calculate a tip based on a percentage?

Back

To calculate a tip, multiply the total bill by the tip percentage (in decimal form). For example, for a $50 bill with a 20% tip, the tip is 50 * 0.20 = $10.

Front

What is the percentage increase if a price goes from $50 to $75?

Back

The percentage increase is calculated as: ((new price - old price) / old price) * 100. So, ((75 - 50) / 50) * 100 = 50%.

Front

If a student answers 16 out of 20 questions correctly, what percentage did they score?

Back

To find the percentage, divide the number of correct answers by the total questions and multiply by 100. (16/20) * 100 = 80%.