Give the step-by-step reasoning process and then the final answer. Don buys recyclable bottles in a small town. Shop A normally sells him 150 bottles, shop B sells him 180 bottles and Shop C sells him the rest. How many bottles does Don buy from Shop C if he is capable of buying only 550 bottles?
Between Shop A and Shop B he buys 150 bottles + 180 bottles = 330 bottles. Thus he can buy 550 bottles - 330 bottles = 220 bottles from shop C.
The final answer: 220.