The full recipe for the banana oat muffins requires 3/4 (or 0.75) cups of old fashion oats. But you are planning to make only 1/3 of the recipe.
To find the amount of oats required for 1/3 of the recipe, we need to multiply the amount required for the full recipe (3/4 cups) by the proportion of the recipe you are making (1/3).
Let's start with the full amount, which is 3/4 cups of oats. Then, we are going to use only 1/3 of this amount. So, we multiply 3/4 by 1/3.
The result of this calculation is 0.25.
So, you will need 0.25 cups of old fashion oats to make 1/3 of the banana oat muffins recipe.