Question

Calculate the following: (a) \(80 \%\) of 75 (b) \(37 \%\) of 250 (c) \(125 \%\) of 550

Short answer

Question: Calculate the required percentages for the given numbers: (a) 80% of 75 (b) 37% of 250 (c) 125% of 550 Answer: (a) 60 (b) 92.5 (c) 687.5

Step-by-step solution

(a) Calculate 80% of 75

To calculate 80% of 75, use the formula mentioned above: Percentage of a number = (Percentage / 100) * Number 80% of 75 = (80 / 100) * 75 80% of 75 = 0.8 * 75 80% of 75 = 60

(b) Calculate 37% of 250

To calculate 37% of 250, use the formula mentioned above: Percentage of a number = (Percentage / 100) * Number 37% of 250 = (37 / 100) * 250 37% of 250 = 0.37 * 250 37% of 250 = 92.5

(c) Calculate 125% of 550

To calculate 125% of 550, use the formula mentioned above: Percentage of a number = (Percentage / 100) * Number 125% of 550 = (125 / 100) * 550 125% of 550 = 1.25 * 550 125% of 550 = 687.5

Key concepts

Percentages in Mathematics

Understanding percentages in mathematics is crucial for many aspects of daily life and essential in various academic disciplines. A percentage represents a fraction of 100 and is often used to compare sizes, express ratios, and measure changes. It is a versatile tool for representing proportions intuitively.

When you see a sign at a store advertising a '30% discount', it means that you pay 30% less than the original price. Conversely, if you hear about a '20% increase in tuition fees', your costs have gone up by that proportion of the previous fees.

In mathematical terms, a percentage is a dimensionless ratio or number expressed as a fraction of 100. To convert a percentage to a decimal for calculation purposes, you divide by 100. For example, 25% becomes 0.25. Recognizing this relationship is key to performing percentage calculations accurately and with confidence.

Basic Arithmetic Operations

Basic arithmetic operations, including addition, subtraction, multiplication, and division, are the cornerstone of mathematics and are particularly relevant when calculating percentages. When dealing with percentages, multiplication and division play a major role.

For instance, to find a percentage of a number, you typically multiply the decimal form of the percentage by the number in question. If you are given a part of a whole and asked to find its percentage, you divide that part by the whole and then multiply by 100. These processes rely on your understanding of multiplication and division as they help you maneuver between whole numbers, fractions, and decimals with ease.

Knowing how to apply these basic operations smoothly is crucial for moving on to more complex mathematical concepts and real-life applications, ensuring that tasks like calculating taxes, discounts, and interest rates become routine.

Calculating Percentages of Numbers

Calculating the percentage of a number is a fundamental skill that combines understanding percentages with basic arithmetic. The standard formula: 'Percentage of a number = (Percentage / 100) * Number' turns the abstract percentage into something concrete.

Let’s demonstrate this with an example from a textbook exercise where you're asked to find 80% of 75. You first convert 80% to a decimal by dividing by 100, giving you 0.8. You then multiply this decimal by 75 to find the result, which is 60. This method is universally applicable, whether you are calculating discounts, interest rates, or any other percentage-based value.

Another vital detail is understanding that percentages can exceed 100%, as they represent ratios or comparisons. For instance, 125% of 550 simply means that amount is 25% more than the full value of 550.