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Finding the Percentage of an Amount
> ... Math > Division and Percentages > Finding the percentage of an amount

Percentages are used a lot in life. For example, we see them in tithing, taxes, and store discounts. In this lesson, you will learn how to do calculations using percentages. Remember, in order to do calculations with percentages, we must first convert them into decimals.

Percent of amount

Video Source (05:02 mins) | Transcript

Adding a percentage amount

Video Source (01:54 mins) | Transcript

Finding a percent vs finding an amount

Video Source (02:56 mins) | Transcript

Here are the things to remember from this lesson:

  • When finding the amount: % as a decimal × total
  • When finding the total cost, do the following:
    • First:
      • Find the percentage of the original amount (% as a decimal × original amount)
    • Second:
      • When adding the percentage (example: taxes), add the percentage amount to the original amount
      • Or, when subtracting the percentage (example: sale), subtract the percentage amount from the original amount
  • Pay attention to what the question is asking! Is it asking for how much something will cost after the percentage is added or subtracted, or is it asking how much money the percentage is? Total amount or percentage amount?

Additional Resources

Practice Problems

  1. How many hours equal 15% of a day? (
    Video Solution
    x
    Solution: 3.6 hours
    Details:

    (Video Source | Transcript)
    )
  2. What is 35% of 200? (
    Solution
    x
    Solution: 70
    Details:
    (This question applies the rule for finding an amount: % as a decimal × total)

    Turn 35% into a decimal by removing the % symbol and moving the decimal point two places to the left.

    \(35\% = {\color{red}0.35}\)

    Multiply 0.35 by 200.

    \({\color{red}0.35} \times 200\)

    The answer is 70.00 or just 70, by dropping the zeros after the decimal point.

    \(70.00 = {\color{red}70}\)
    )
  3. If a computer costs $850 and it is on sale for 15% off, how much has the price been reduced? (
    Solution
    x
    Solution: $127.50
    Details:
    15% of $850 is: \(0.15 \times $850 = $127.50\).
    This is the amount that the price has been reduced.
    )
  4. If a dress costs $150 and it is on sale for 20% off, what is the sale price of the dress? (
    Video Solution
    x
    Solution: $120
    Details:

    (Video Source | Transcript)
    )
  5. If a bicycle costs $500 and the sales tax is 6%, what is the total cost of the bicycle with tax included? (
    Solution
    x
    Solution: $530
    Details:
    The price of the bicycle is $500 and the sales tax is 6%
    image with a blue section on the left and pink section on the right. The left section reads: Price or the Bicycle $500. The right section reads: Sales Tax 6%

    The price of the bicycle represents 100% of the price.
    image with a blue section on the left and pink section on the right. The left section reads: Price or the Bicycle 100% (in red text). The right section reads: Sales Tax 6%

    Combine 100% of the bicycle price with 6%
    image with a blue section on the left and pink section on the right. The left section reads: Price or the Bicycle 100% with a red plus symbol to the right of it between the left and right sections. The right section reads: Sales Tax 6%

    100% + 6% = 106%. This new percent of 106% represents the new total cost of the bicycle.
    image with a blue section on the left, pink section on the right and a tan section at the bottom spanning underneath both the upper left and right sections. The left upper section reads: Price or the Bicycle. The right section reads: Sales Tax. The bottom section reads 106%.

    Turn 106% into a decimal by removing the % symbol and moving the decimal to the left 2 places.

    \(106\% = {\color{red}1.06}\)

    Use this decimal to multiply by 500 to get the total cost of the bicycle.

    \(1.06 \times {\color{red}500}\)

    $530 is the total cost of the bicycle with the tax.

    \(1.06 \times 500 = {\color{red}530.00}\)
    )

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