4. For each ornament that a worker makes, he is paid \( \$ 1.15 \). He makes 4 ornaments every 15 minutes. Find the amount earned by the worker if he works for 3 hours.

To find the amount earned by the worker in 3 hours, we can follow these steps: 1. **Calculate the number of 15-minute intervals in 3 hours:** \[ 3 \text{ hours} = 3 \times 60 \text{ minutes} = 180 \text{ minutes} \] \[ \text{Number of 15-minute intervals} = \frac{180 \text{ minutes}}{15 \text{ minutes}} = 12 \] 2. **Calculate the total number of ornaments made in 3 hours:** Since the worker makes 4 ornaments every 15 minutes: \[ \text{Total ornaments} = 4 \text{ ornaments} \times 12 = 48 \text{ ornaments} \] 3. **Calculate the total earnings:** The worker earns \( \$1.15 \) for each ornament: \[ \text{Total earnings} = 48 \text{ ornaments} \times 1.15 \text{ dollars/ornament} = 55.2 \text{ dollars} \] Thus, the amount earned by the worker if he works for 3 hours is \( \boxed{55.20} \) dollars.