Calculating Total Smoothie Fraction

Lucas is preparing a special smoothie that consists of three different types of fruit. He uses fruits in the following proportions:

- $\f\frac{3}{5}$ of a banana puree,
- $\f\frac{1}{3}$ of a strawberry puree,
- $\f\frac{1}{4}$ of an apple juice.

Lucas realizes that he has mistakenly calculated the total amount of the smoothie. To fix it, he decides to combine all the proportions he used into a single fraction that represents the total fraction of the smoothie made. What is this fraction?