A.(一級(jí)車數(shù)+二級(jí)車數(shù)+三機(jī)車數(shù))÷各級(jí)車數(shù)總和
B.2(一級(jí)車數(shù)+二級(jí)車數(shù)+三機(jī)車數(shù))÷各級(jí)車數(shù)總和
C.(3×一級(jí)車數(shù)+2×二級(jí)車數(shù)+1×三機(jī)車數(shù))÷各級(jí)車數(shù)總和
D.(1×一級(jí)車數(shù)+2×二級(jí)車數(shù)+3×三機(jī)車數(shù))÷各級(jí)車數(shù)總和