To find out how many pages Brian can read in 3.5 hours, we first need to determine his reading rate.
Brian can read 80 pages in 2 hours. We can calculate his reading rate as follows:
\[ \text{Reading rate} = \frac{\text{Total pages}}{\text{Total time}} = \frac{80 \text{ pages}}{2 \text{ hours}} = 40 \text{ pages per hour} \]
Now that we know his reading rate is 40 pages per hour, we can calculate how many pages he can read in 3.5 hours:
\[ \text{Pages read in 3.5 hours} = \text{Reading rate} \times \text{Time} = 40 \text{ pages/hour} \times 3.5 \text{ hours} = 140 \text{ pages} \]
Thus, Brian can read 140 pages in 3.5 hours.