a/
\frac{58.68,27+60.26,1+61.1,13+62.3,59+64.(100-68,27-26,1-1,13-3,59)}{100}=58,7541
b/
0,91%__________91 ngtu Ni(64)
68,27%_________6827 nt Ni 58
26,1%__________2610 nt Ni 60
1,13%___________113 nt Ni 61
3,59%____________359 nt Ni 62
c/ m% (Ni 60)/NiCl2= \frac{60}{58,7541.35,5.2}.100=46.24 %...