1. **State the problem:** A, B, and C can complete a piece of work in 20, 30, and 60 days respectively. They work together and earn 3600. We need to find B's share of the money. 2. **Formula and concept:** The share of each person is proportional to the amount of work they do. Work done is inversely proportional to the time taken. So, work done by A, B, and C per day are $\frac{1}{20}$, $\frac{1}{30}$, and $\frac{1}{60}$ respectively. 3. **Calculate total work done per day together:** $$\frac{1}{20} + \frac{1}{30} + \frac{1}{60} = \frac{3}{60} + \frac{2}{60} + \frac{1}{60} = \frac{6}{60} = \frac{1}{10}$$ 4. **Calculate B's share of the work:** $$\text{B's work fraction} = \frac{\frac{1}{30}}{\frac{1}{10}} = \frac{1}{30} \times \frac{10}{1} = \frac{10}{30} = \frac{1}{3}$$ 5. **Calculate B's share of the money:** $$\text{B's share} = \frac{1}{3} \times 3600 = 1200$$ **Final answer:** B's share of the money is 1200.