1. **State the problem:** We have a function $L(T)$ representing the pages left to read after $T$ hours, where the book has 150 pages and Ray reads at 25 pages per hour. 2. **Formula:** The pages left to read after $T$ hours is given by $$L = 150 - 25T$$ This is because every hour, 25 pages are read, so the pages left decrease by 25 each hour. 3. **Domain:** The domain is the set of possible values for $T$ (time in hours). Since Ray cannot read negative time and cannot read beyond finishing the book, $T$ ranges from 0 to when $L=0$: Set $L=0$: $$0 = 150 - 25T$$ $$25T = 150$$ $$T = \frac{150}{25} = 6$$ So the domain is: $$0 \leq T \leq 6$$ 4. **Range:** The range is the set of possible values for $L$ (pages left). At $T=0$, $L=150$ pages, and at $T=6$, $L=0$ pages. So the range is: $$0 \leq L \leq 150$$ 5. **Summary:** - Domain: $0 \leq T \leq 6$ - Range: $0 \leq L \leq 150$ This means Ray reads from time 0 to 6 hours, and pages left decrease from 150 to 0 accordingly.