С2 и С3 С2*С3/(C2+C3)=15*25/40=75/8
C4 И С5 = 10+20=30
С1 И С6 C8=С1*С6/(C1+C6)=5*30/35=30/7
C7=75/8+30=39 3/8
C=C8*C7/(C7+C8)
С2 и С3 С2*С3/(C2+C3)=15*25/40=75/8
C4 И С5 = 10+20=30
С1 И С6 C8=С1*С6/(C1+C6)=5*30/35=30/7
C7=75/8+30=39 3/8
C=C8*C7/(C7+C8)