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

### Instruction:
 卡尔文每周五天在午餐时从自动贩卖机购买一袋价格为0.50美元的薯片。4周后，卡尔文在薯片上花了多少钱？


### Response:
 卡尔文每周购买薯片5天，每袋价格为0.50美元，所以每周他在薯片上花费5 x 0.5 = 2.50美元。
4周后，卡尔文在薯片上花费4 x 2.5 = 10.00美元。