1. **State the problem:** Four packets of tea cost 1.28. We need to find the cost of three packets. 2. **Formula and approach:** To find the cost of three packets, first find the cost of one packet by dividing the total cost of four packets by 4. 3. **Calculate the cost of one packet:** $$\text{Cost of one packet} = \frac{1.28}{4}$$ 4. **Simplify the division:** $$\text{Cost of one packet} = \frac{\cancel{1.28}}{\cancel{4}} = 0.32$$ 5. **Calculate the cost of three packets:** $$\text{Cost of three packets} = 3 \times 0.32$$ 6. **Multiply:** $$\text{Cost of three packets} = 0.96$$ **Final answer:** The cost of three packets of tea is 0.96.