To determine how many chapters Raj can read in 64 minutes, you can divide the total time by the time it takes him to read one chapter.
Raj reads one chapter in 16 minutes.
Now, divide 64 minutes by 16 minutes per chapter:
\[ \text{Number of chapters} = \frac{64 \text{ minutes}}{16 \text{ minutes per chapter}} = 4 \]
So, Raj can read 4 chapters in 64 minutes.