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.?  Choices
A) 266.69  B) 266.67  C) 266.66  D) 263.66  E) 266.61
Explanation:   Let us take 100x kgs of ore. Now it contains 25x kgs of alloy and it contains 90% (25x) kgs of iron.   90% (25x) = 60 kg ⇒ x = 60×10090×12560×10090×125 = 8383   So iron ore required = 100 × 8383 = 266.66   Answer: 263.66
<result>D</result>
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.?