arama: 656,25·64,8%=65625/100·64,8/100=65625/100·0,648=65225/100·648/1000=simplif=425,25kg
zinc: 656,25·32,8%=65625/100·32,8/100=65625/100·0,328=65625/100·328/1000=simplif=215,25·kg
plumb:
656,25·2,4%=65625/100·2,4/100=65625/100·0,024=65625/100·24/1000=simplif=15,75kg
425,25+215,25+15,75=656,25kg
