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

### Instruction:
 蒂姆在中餐外卖上花了50美元。其中80%的费用用于4份主菜。剩下的钱用于两份每份价格相同的开胃菜。一份开胃菜的价格是多少？


### Response:
 主菜的费用是$50.00 x 80% = $<<50*80*.01=40.00>>40.00。
所以开胃菜的费用是$50.00 - $40.00 = $<<50-40=10.00>>10.00。
每份开胃菜的价格相同，所以价格是$10.00/2 = $<<10/2=5.00>>5.00。