(c). 此鑄砂是屬於多少峯砂？: ________ (殘留砂有四個超過 10%，四峯砂為鑄造用砂首選)

(c). 計算過程 (注意：配料總重量為四種配料重量之和) C₁=50x3.6/100+50x0.2/100+1x99/100 =1.80+0.10+0.99 =2.89 Si₁=50x1.80/100+50x0.2/100+1x50/100 =0.90+0.10+0.5 =1.50 C₂=2.89(1+0.1)=3.179 Si₂=1.50(1-0.1)=1.350 C=3.179x100/102=3.117=____1____ % Si=1.350x100/102=1.324=____2____% CE=3.117+1/3(1.324)=3.558=____3____ % 1.