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How Do You Figure Out How Much Something is Marked Down?

Madeline went to buy a new television so she could watch her favorite show, "Algebra Ninjas in Space." She bought a television whose original price was $325, but was marked down 20%. How much did she spend on the television?

Summary

  1. 'c' represents the amount of money Madeline spent on the TV
  2. 325 was the original price of the TV
  3. 0.2 is 20% written as a decimal
  4. Multiply 0.2•325 to get the amount the TV was marked down
  5. The amount spent is the original price minus the amount it was marked down
  6. Madeline spent $260 on her new TV

Notes

    1. 'c' is a variable that represents the amount of money Madeline spent on the television
    1. To find out how much Madeline spent, we need to find how much the TV actually cost
    2. We need to subtract the amount it was marked down from how much it cost originally
    3. 20% off is a pretty good deal!
    1. The amount the television was marked down was 20% of the original price
    2. So we need to figure out 20% of 325 and subtract that value from 325, the original price
    1. If something at a store is marked down by a percent, it is marked down by that percent of the original price
    2. So in our problem, the amount the TV is marked down is 20% of 325
    1. To find the amount the TV was marked down, we need to take 20% of 325
    2. But since it's hard to work with percents, we need to convert 20% to a decimal
    3. To convert, drop the percent symbol and move the decimal point two places to the left
    4. So 20% becomes 0.2
    5. Now we can multiply 0.2 by 325 to get the amount marked down
    1. The original price was 325
    2. The amount it was marked down was 20% of 325, which is 0.2•325
    1. 'c' is a variable that represents the amount of money Madeline spent on the television
    2. If we subtract the amount the TV was marked down from the original price, it will give us the new price
    3. So we have 325-(0.2•325), which equals c, the amount Madeline actually paid for the TV
    1. 'c' is a variable that represents the amount of money Madeline spent on the television
    1. 'c' is a variable that represents the amount of money Madeline spent on the television
    1. The order of operations says we need to do what's inside the parentheses first
    2. So multiply out 0.2•325 to get 65
    1. Now we can subtract 65 from 325
    2. When we subtract, we get 260
    3. This is the new price of the television
    1. 'c' is a variable that represents the amount of money Madeline spent on the television
    2. So Madeline spent $260 on her new television
    1. $260 down from $325? That's a pretty good deal!