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

### Instruction:
 阿里和莎拉一共吃了80个小苹果。阿里吃的苹果是莎拉的4倍。莎拉吃了多少个苹果？


### Response:
 设阿里吃的苹果数为A，莎拉吃的苹果数为S。
我们有：A + S = 80个苹果
并且：A = <<4=4>>4S
这意味着：4S + S = 80
所以：5S = <<80=80>>80
因此，莎拉吃的苹果数为：S = 80 / 5 = <<80/5=16>>16个苹果。