Problem 60 - Algebra 1

Question

Find the number. $$ 7 \% \text { of } 28.5 $$

Step-by-Step Solution

Answer

The 7% of 28.5 is 1.995.

Step 1 - Percentage formula

Recall the formula to calculate the percentage which is (part/whole) * 100.

Step 2 - Substitute values

Here, we need to calculate 7% of 28.5. So, substitute these values into the formula. That is, (7/100) * 28.5.

Step 3 - Calculation

Do the multiplication to get the result. Which will be 1.995, rounded to the nearest hundredth.

Key Concepts

Percentage Formula

Understanding percentages is crucial in many areas, such as finance, science, and everyday tasks. A percentage means "per hundred" and is a way to express a number as a fraction of 100. The percentage formula is versatile and can be applied to find what part of one thing represents of another. To calculate the percentage of a number, use the formula:

• Percentage = \( \frac{\text{Part}}{\text{Whole}} \times 100 \)

This basic formula helps in calculating percentages. However, when finding a percentage of a certain number, the formula is a bit different. Instead, it looks like this:

• Part = \( \text{Percentage} \div 100 \times \text{Whole} \)

This adjusted formula will help us solve problems where we need to find "say, 7% of 28.5."

Substitute Values

Substituting values into formulas is a critical step in solving math problems. It involves replacing variables with specific numbers from the problem. For instance, if you're tasked with finding 7% of 28.5, you need to plug these numbers into the percentage calculation formula.

• Start by identifying the percentage: 7%.
• Next, identify the whole quantity which the percentage refers to: 28.5.

With this information, replace the percentage and whole in the formula as follows:

• Substitute them into our formula: \( \text{Part} = \frac{7}{100} \times 28.5 \)

After substituting, you're set to proceed to the next step, which involves calculating the result.

Multiplication

Once you've substituted the values into your formula, it's time to perform the multiplication. This step is about calculating the actual number, which is the part or portion of the whole you are interested in. Here's how you do it:

• Take the fraction of the percentage: \( \frac{7}{100} \)
• Multiply it by the whole amount: \( 28.5 \)
• Mathematically, this looks like: \( \frac{7}{100} \times 28.5 = 1.995 \)

In our example calculation, multiplying gives us 1.995. Usually, depending on the context, you may want these results to be rounded. Here, 1.995 is rounded to the nearest hundredth if necessary. Multiplication helps turn words into numeric answers, solidifying your understanding of percentage problems.