Final answer:
To determine the cost of 20 notebooks, we find that the unit price is $1.50 per notebook by dividing $12 by 8 notebooks. Multiplying the unit price of $1.50 by 20 notebooks gives us the total cost of $30.
Step-by-step explanation:
The question asks for the cost of 20 notebooks given that eight notebooks are sold for $12. To find this, we can use the unit price, which is the cost per single notebook. First, we calculate the unit price by dividing the total cost by the number of notebooks.
Unit price = Total cost / Number of notebooks
Unit price = $12 / 8 notebooks = $1.50 per notebook
Now that we have the unit price, we can find the cost for 20 notebooks by multiplying the unit price by 20.
Cost for 20 notebooks = Unit price x Number of notebooks
Cost for 20 notebooks = $1.50 x 20 = $30
Therefore, the cost for 20 notebooks is $30.