Examveda

Out of the total production of iron from hematite, an ore of Iron, 20% of the ore gets wasted, and out of the remaining iron, only 25% is pure iron. If the pure iron obtained in a year from a mine of hematite was 80,000 kg, then the quantity of hematite mined from that mine in the year is

A. 5,00,000 kg

B. 4,00,000 kg

C. 4,50,000 kg

D. None of these

Answer: Option B

Solution(By Examveda Team)

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 = $$\frac{{80 \times 25}}{{100}} = 20\,{\text{kg}}$$
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 =$$\,\frac{{100}}{{20}} \times 80000 = \,$$    $$400000\,{\text{kg}}$$   hematite.
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