40+(x-60)*0.2=60+(x-200)*0.3 40+0.2x-12=60+0.3x-600.3x-0.2x=40-120.1x=28x=28÷0.1x=280
40+0.2x-0.2×60=60+0.3x-0.3×20040+0.2x-12=60+0.3x-600.2x+28=0.3x0.3x-0.2x=280.1x=28x=280