Question

Out of the total production of iron from hematite, an ore of iron, 20% of the ore gets wasted. Out of the remaining iron, only 25% is pure iron. If the pure iron obtained in a year from a mine of hematite was 80000 kg, then the quantity of hematite mined in the year is

• A. 400000 kg
• B. 500000 kg
• C. 450000 kg
• D. 600000 kg

Answer 1

Answer: (A)

400000 kg

Answer 2

Let 100 kg of hematite be obtained then 20% of it get wasted that means 80 kg of ore remains.

Pure iron = 25$\%$ of remaining ore = 80$\times\frac{25}{100}$
= 20 kg.
20 kg pure Iron is obtained from 100 of hematite.

1 kg pure Iron is obtained from = $\frac{100}{20}$ hematite;

Then, 80000 kg pure Iron is obtained from = $(\frac{100}{20})\times80000$
= 400000 kg hematite.
So the correct option is (A)