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To solve problems involving percentages, it's important to understand how to convert a percentage into a decimal. This process is straightforward, but crucial for performing accurate calculations. Start by dividing the percentage by 100. This step transforms the percentage into a decimal form.
For example, to convert 10% into a decimal, you divide 10 by 100:
\[\frac{10}{100} = 0.10\]
Similarly, for 75% you divide 75 by 100:
\[\frac{75}{100} = 0.75\]
And for 24%, divide 24 by 100:
\[\frac{24}{100} = 0.24\]
Notice how simple it is to perform this conversion. Once you have your decimal, you can use it in various mathematical operations, like multiplication.

Once you've converted your percentage into a decimal, the next step is to multiply this decimal by the given amount you want to find the percentage of.
For example, if you need to find 10% of \(2.90, start by converting 10% into a decimal (0.10), then multiply that by \)2.90:
\[0.10 \times 2.90 = 0.29\]
So, 10% of \(2.90 is \)0.29.
Let's take another example: calculate 75% of \(1250. First, convert 75% into a decimal (0.75), then multiply it by \)1250:
\[0.75 \times 1250 = 937.50\]
Therefore, 75% of \(1250 is \)937.50.
Finally, for 24% of \(580, convert 24% into a decimal (0.24), and multiply by \)580:
\[0.24 \times 580 = 139.20\]
Hence, 24% of \(580 is \)139.20.
This approach of converting the percentage to a decimal and then multiplying makes it easier to understand and calculate percentages for any amount.

Simple interest calculations often require the use of percentages. To find the simple interest earned over a period, you can use the formula:
\[ \text{Simple Interest} = P \times r \times t \]
where:

• P is the principal amount (initial sum of money)
• r is the rate of interest per period (as a decimal)
• t is the time the money is invested or borrowed for, in periods

For example, if you deposit \(1000 at an interest rate of 5% per year for 3 years, first convert the percentage rate into a decimal by dividing by 100:
\[5\text{%} = \frac{5}{100} = 0.05\]
Now, use the simple interest formula:
\[ \text{Simple Interest} = 1000 \times 0.05 \times 3 = 150\]
So, the simple interest earned over 3 years is \)150.
Understanding these core concepts and how they interplay will make solving any percentage or simple interest problems much easier.