Problem set #1 problem 3

I was a little bit confused about is it mineral=silt+clay+sand which means 100%?

Here is a hint question - Are there any other mineral particles or components (besides sand, silt and clay) mentioned in that question?

Does the clay 35% and silt 60% indicate that the remaining 5% is sand or that the remaining 5% is water and organic matter?

The remaining percentage refers to sand