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

### Instruction:
 一根烤肉串有4块牛肉。一块价值25美元的牛肉可以切成80块。为了做40根烤肉串，西蒙需要花多少钱？


### Response:
 一块牛肉可以做80/4 = <<80/4=20>>20根烤肉串。
西蒙需要2块牛肉来做40根烤肉串，所以他必须花费25美元 x 2 = $<<25*2=50>>50。