One. The unknown equations set according to the topic need not be solved.

1. children x, young people X+6, old people X+6-4 = X+2. X+X+6+X+2 = 83, which means 3x+8=83.

2.X stands for teenagers, X-6 stands for children and X-4 stands for teenagers. X-6+X+X-4 = 83, which means 3x- 10 = 83.

3. Old people are X, young people are X+4, and children are X+4-6 = X-2. X+X+4+X-2 = 83, which means 3x+2=83.

2. Need a formula solution.

Let b be x, then a is 1.2X,

If we give the number B 3600, the two numbers are as many as X+3600= 1.2X, and the solution is X = 18000, that is, A 2 1600 and B 18000.