How are part-to-part ratios different from part-to-whole ratios

Say you have fruit:
one part of 5 apples
another one part of 8oranges.
Adding together equaling a total whole amount of fruit equaling 13.

If you do a part to part ratio
Ex. apples to oranges.
5:8

If you do part to whole ratios you are using a part to the whole number.
Say oranges to whole:
8:13

Iwould like to think so. what’s the question you need with?