Answer:
70%of 2000 = 1400
2000 tonnes of hematite contains 1400 tonnes iron oxide .
1400 tonnes of fe2O3
fe2O3 have molar mass 159.69
calculate moles = given mass/molar mass
moles = 1400000000/159.69
moles = 8766986
one mole contains = 112 g of fe
so 8766986 moles will contain = 112×8766986
= 981,902,432 grams of ferrous
which is nothing but equal to 981.90 tonnes of iron!!