The answer 0.12 represents the portion of books in the library that are how-to books on carpentry.
This is calculated as follows:
- There are 0.3 (30%) how-to books in the library.
- Out of those, 0.2 (20%) deal with carpentry.
- To find the portion of the entire library that are how-to books on carpentry, you multiply 0.3 by 0.2, which gives you 0.12 (12%).
Thus, 0.12 represents the portion of the books in the library that are how-to books specifically about carpentry.