Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 约翰买了晚餐盘和银器。银器花费了20美元。晚餐盘的价格是银器价格的50%。他一共支付了多少钱？


### Response:
 晚餐盘的价格是$20 * 0.5 = $<<20*0.5=10>>10。
所以他一共支付了$10 + $20 = $<<10+20=30>>30。