public class Test3 {

    public static void main(String[] args) {

        int men;
        int women;
        int kids;
        for (men=0; men <= 50 / 3; men++) {
            for (women=0; women <= 50 / 2; women++) {
                for (kids=0; kids <= 50; kids++) {
                    if ((3 * men + 2 * women + kids == 50)
                            && (men + women + kids == 30)) {
                        System.out.println("男人:" + men + ", 女人:" + women
                                + ", 小孩:" + kids);
                    }
                }
            }
        }
    }
}

------解决方案--------------------
package test;

public class Test {

	public static void main(String[] args) {

		int x; // 男人    
		int y; // 女人
		//小孩， 因为   x+y+z = 30  所以  z = 30-x-y
		System.out.println("男人\t女人\t小孩(30-x-y)");
		for (x = 0; x <= 50/3; x++) {    //男人数不会超过50 /3 个
			for (y = 0; y <= 50/2; y++) {  //女数不会超过50 /2 个
				if (3 * x + 2 * y + (30 - y - x) == 50) {
					System.out.println(x +"\t" + y + "\t"
							+ (30 - x - y));

				}
			}
		}
	}
}


------解决方案--------------------
唉，好笨，自己想不出来，只好看别人的了。

------解决方案--------------------
其实women和kids的范围可以再缩小一下
0《men《5/3
0《women《(50-men*3)/2
0《kids《50-men*3-women*2

------解决方案--------------------
这个问题很有趣，刚看到题目我还想写呢！但是1楼已经的非常好了，我就懒得写了。

------解决方案--------------------
public class Test02 {
	public static void main(String[] args) {
		int men ,women,kids;
		for(men =0;men<=10;men++){
			for (women =0; women <= 30; women++) {
				for (kids =0; kids <= 30; kids++) {
					if((men*3+women*2+kids==50) && (men+women+kids==30)){
						System.out.println("men有    "+men+"   women有"+women+"  kids有"+kids);						
					}
				}
			}
		}
	}
}

------解决方案--------------------
731564363