To model the total amount of water \( w \) that Martina used, you can use the equation:
\[ w = 8.5 \times 5 \]
In this equation, \( 8.5 \) represents the amount of water in ounces that she put into each container, and \( 5 \) represents the number of containers. So, to calculate the total amount of water, \( w \) would be the product of those two values.
If you want to rewrite the equation in the form you've provided:
\[ \frac{w}{1} = 8.5 \times 5 \]
So \( w \) is equal to the total amount of water used, which is \( 42.5 \) ounces.