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

### Instruction:
 派对上有50个孩子。其中三分之五是男孩。有多少个孩子是女孩？


### Response:
 50 x 3/5 = 30个孩子是男孩。
所以有50 - 30 = <<50-30=20>>20个孩子是女孩。