Ted bought 3 notebooks and 5 folders for $27
You know that each notebook cost $4, to the cost for the notebooks he bought can be calculated as the price per notebook multiplied by the number of notebooks bought:
→ He spent $12 on the three notebooks.
Let "f" represent the cost per folder, then 5f represents the cost of all folders, we know that the notebooks plus the folders cost $27, then:
From this expression, you can determine the cost of each folder, first subtract 12 from both sides of the equation:
Now divide both sides by 5 to determine the value of "f":
f=3 → This means that each folder costs $3