Sunil works at the library for 3 weeks longer than \( \frac{3}{4} \) of the semester. A semester is 20 weeks long at Sunil's college. How many weeks in the semester does Sunil work at the library?

To find out how many weeks Sunil works at the library, we start by calculating \( \frac{3}{4} \) of the semester length. A semester is 20 weeks long, so: \[ \frac{3}{4} \times 20 = 15 \text{ weeks} \] Sunil works for 3 weeks longer than this amount: \[ 15 + 3 = 18 \text{ weeks} \] Thus, Sunil works at the library for **18 weeks** during the semester.