sphalerite, also called blende, or zinc blende, zinc sulfide (ZnS), the chief ore mineral of zinc.
According to question
% of zinc is 30
It means 100 g of ZnS gives 30g of Zn
1 g of ZnS gives =30/100 or 0.3 g of Zinc
1000 g or 1Kg of Zinc gives = 0.3 ×1000
= 0.3 ×>10^3 gram
1000kg gives = 0.3 ×10^3 ×1000
= 0.3 × 10^6 g of Zinc or
3.0 × 10^5 g of Zinc