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

### Instruction:
 丽贝卡为她的野营旅行购买了22件物品，包括帐篷桩、饮料包和瓶装水。她购买的饮料包是帐篷桩的3倍。她还购买了比帐篷桩多2个瓶装水。她购买了多少个帐篷桩？


### Response:
 设帐篷桩的数量为x
饮料包：3x
瓶装水：x+2
总数：x+3x+x+2=22
5x+2=22
5x=20
x=<<4=4>>4个帐篷桩