2 10=2*3*5*7

∫ Three years old adds up to 18.

So only 6+5+7= 18.

So they are five, six and seven years old.

2、

There are x black rabbits.

So there are 8x white rabbits.

x=8x-28

x=4

So there are 4 black rabbits and 32 white rabbits.

3、

First, Li Minghe Xiaohua is not a brother and sister;

Second, Zhang Hu and Xiaohong are not brothers and sisters;

Third, Zhang Hu and Kobayashi are not brothers and sisters;

Xiaohong and Xiaolin are not Zhang Hu's sisters.

So Zhang Hu's sister is Xiaohua;

So there are two situations left:

The first possibility is: Li Ming's sister is Xiaohong, and Wang Ning's sister is Xiaolin;

The second possibility is that Li Ming's sister is Xiao Lin and Wang Ning's sister is Xiao Hong.

For the first possibility, the second game is Zhang Hu and Kobayashi versus Li Minghe Wang Ning's sister. Then there is a three-person mixed competition, which is unrealistic, so the first one may not be established, and only the second one may be reasonable.

That is, Li Ming's sister is Xiao Lin and Wang Ning's sister is Xiao Hong.