Give the step-by-step reasoning process and then the final answer. Rebecca drinks half a bottle of soda a day. She bought three 6-packs of sodas the last time she was at the store. How many bottles of soda will she have left after four weeks?
Rebecca bought 3 * 6 = 18 bottles of soda. A week is 7 days, so she will drink 4 * 7 = 28 half bottles of soda in four weeks. A bottle is two half bottles, so she will drink 28 / 2 = 14 bottles of soda in four weeks. Thus, after 4 weeks, she will have 18 - 14 = 4 bottles of soda left.
The final answer: 4.