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

### Instruction:
 朱莉比她妹妹玛吉大3岁，但比她哥哥拉尔夫小2岁。如果朱莉今年10岁，那么玛吉和拉尔夫的年龄之和是多少？


### Response:
 玛吉比朱莉小3岁，所以玛吉今年7岁。
拉尔夫比玛吉大2岁，所以拉尔夫今年12岁。
玛吉和拉尔夫的年龄之和是7岁+12岁=19岁。