净利润=(4,100-100)×(1-25%)=3,000万元
营业净利率=3,000/8,000=37.5%
总资产周转率=8,000/10,000=80%
权益乘数=10,000/(10,000-4,000)=5/3
净资产收益率=37.5%×80%×5/3=50%
