In 1 kg mixture of sand and iron, 20% is iron. How much sand should be added so that the proportion of iron becomes 10%?  Choose the correct option.
A) 1 kg  B) 200 gms  C) 800 gms  D) 1.8 kg  E) None of these
In 1 kg mixture quantity of iron = 200 gm   Let x gm sand should be added, then   10% of (1000 + x) = 200   \ x = 1000 gm = 1 kg   1 kgnswer 1 kg
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In 1 kg mixture of sand and iron, 20% is iron. How much sand should be added so that the proportion of iron becomes 10%?