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what is 70 of 40

what is 70 of 40

2 min read 02-02-2025
what is 70 of 40

What is 70% of 40? A Step-by-Step Guide

Finding a percentage of a number is a common mathematical task. This article will clearly explain how to calculate 70% of 40, providing a step-by-step process that's easy to understand, even for those who aren't math experts. We'll also explore different methods to solve this problem.

Understanding Percentages

Before we begin, let's quickly recap what percentages represent. A percentage is a fraction out of 100. So, 70% means 70 out of 100, or 70/100.

Method 1: Using Decimal Conversion

This is often the easiest method. We convert the percentage to a decimal and then multiply it by the number.

  1. Convert the percentage to a decimal: To do this, divide the percentage by 100. 70% divided by 100 is 0.70 (or simply 0.7).

  2. Multiply the decimal by the number: Now, multiply 0.7 by 40. 0.7 * 40 = 28

Therefore, 70% of 40 is 28\boxed{28}.

Method 2: Using Fractions

We can also solve this using fractions.

  1. Express the percentage as a fraction: 70% is equivalent to the fraction 70/100.

  2. Simplify the fraction (optional): The fraction 70/100 can be simplified by dividing both the numerator and the denominator by 10, resulting in 7/10.

  3. Multiply the fraction by the number: Multiply 7/10 by 40. (7/10) * 40 = 280/10

  4. Simplify the result: 280/10 simplifies to 28.

Again, we find that 70% of 40 is 28\boxed{28}.

Method 3: Using Proportions

This method is useful for understanding the relationship between the percentage and the whole.

  1. Set up a proportion: We can set up a proportion as follows:

    70/100 = x/40

    Where 'x' represents 70% of 40.

  2. Cross-multiply: Multiply 70 by 40 and 100 by x:

    70 * 40 = 100 * x

    2800 = 100x

  3. Solve for x: Divide both sides by 100:

    x = 2800 / 100 = 28

Once more, we arrive at the answer: 70% of 40 is 28\boxed{28}.

Conclusion

Regardless of the method you choose, the answer remains the same: 70% of 40 is 28. Understanding these different approaches will help you confidently calculate percentages in various situations. Choose the method that feels most comfortable and efficient for you.

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