х*(1-1/4)*(1-4/9)-6400=0,15х
х*3/4*5/9-6400=0,15х
х*15/36-6400=0,15х
5/12х-3/20х=6400
25/60х-9/60х=6400
16/60х=6400
16х=6400*60
16х=384000
х=384000/16
х=24000
х*(1-1/4)*(1-4/9)-6400=0,15х
х*3/4*5/9-6400=0,15х
х*15/36-6400=0,15х
5/12х-3/20х=6400
25/60х-9/60х=6400
16/60х=6400
16х=6400*60
16х=384000
х=384000/16
х=24000