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

### Instruction:
 约翰的游泳池比莎拉的游泳池深5英尺，如果约翰的游泳池深15英尺，莎拉的游泳池有多深？


### Response:
 设x为约翰的游泳池的深度
2*x + 5=15
2x=10
x=<<5=5>>5