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 kg. of the ore are needed to obtain 60 kg. of pure iron.???


1-250
2-275
3-300
4-166.66

• According to me :-
  ore-25%alloy+75%(no iron)
  in 25% alloy -->90%iron
  so,
  let ore is x kg
  x*25%*90% = 60kg
  by soling this i m getting 266.66
  but option is 166.66 plz check option.
  
• 9 years agoHelpfull: Yes(9) No(9)
• option d is correct.
  but its 266.66 not 166.66
  Let there is 100 kg of ore
  25% ore contains 90% of iron ,means 25 kg contains
  25*90/100= 22.5kg iron
  
  60 kg of iron =60*100/22.5 = 266.66
  hence solved
• 9 years agoHelpfull: Yes(5) No(1)
• 25% of alloy has 90% iron--means 25*90/100=22.5 kg iron
  
  so----in 100kg has 22.5 kg iron
  
  we want 60 kg pure iron-----100kg*60/22.5=600/22.5=6000/225=266.66
• 9 years agoHelpfull: Yes(3) No(0)
• hence proved
  
• 9 years agoHelpfull: Yes(2) No(0)
• answer is 4 -166.66
• 6 years agoHelpfull: Yes(0) No(1)