32岁算式X：徒弟年龄；Y：师傅年龄X+Y=56 → X=56-Y(X+Y-X)/4=(Y+Y-X)/5→5*Y=4*(2Y-X)→5*Y=4*(2Y-56+Y)→7Y=56*4 → Y=32不要假设=56*4/(5+2)=32