Question

An ore contains 25% of an alloy that has 90% iron. Other than this, in remaining 75% of the ore ,there is no iron. How many kgs of the ore are needed to obtain 60 kg. Of pure iron.?

Answer 1

Let there is 100 kg of ore.

25% ore contains 90% off Iron that means 25 kg contains;

25*90/100 = 22.5 kg Iron.

22.5 kg Iron contains 100 kg of ore.

Then, 1 kg of iron contains = 25/100 kg ore;

Hence, 60 kg iron contains = 100*60/22.5 = 266.66 kg ore.